DYNAS (from Dynamic Selectivity[1][2][3]) is a dynamic analog filtering and tuning technology to improve the reception of FM radio broadcasts under adverse conditions.
Overview
The trademarked[4] DYNAS system is based on the same principles as the In Channel Select (ICS) system by H.u.C. Elektronik. The novel tracking filter arrangement was originally conceived by the German engineer Jens Hansen[2][3] in 1982.[5] The concept was prototyped as High Select in summer 1983.[5] With funding from innovation funds of the city of Berlin, Hansen left Bosch/Blaupunkt to start, with companion Klaus Müller-Catito, his own company H.u.C. Elektronik in 1984.[5][6][7][8][nb 1][nb 2] When licensing negotiations with his former employer failed,[8] the system was marketed in the early 1990s as DYNAS by the German Telefunken electronic[2] (a spin-off of AEG-Telefunken and DASA, firming as TEMIC TELEFUNKEN microelectronic since 1992),[9][10][11][12][13][14] who, with the related Telefunken Semiconductors[3][2] (the former AEG-Telefunken Halbleiterwerk in Heilbronn), also designed integrated circuits implementing the system, the TEMIC/TFK[3] U4290B (stand-alone FM IF DYNAS system in 68-pin PLCC package),[3][2][15][16][17][4][12][18] U4291B (DYNAS coprocessor)[18] and U4292B (software-controlled DYNAS system in 44-pin SSO package).[1][18]
Compared to conventional receivers, DYNAS has a more than 26 dB better selectivity and a typically twice as good sensitivity (improved by 6 dB) thereby almost doubling the reception area and allowing to receive even extremely noisy stations.[1] This is achieved by an adaptive bandwidth of the IF filter and by dynamically tracking of the center frequency of the IF filter in real-time.
With a transmitter spacing of 200 kHz an undisturbed reception in stereo is possible, with 100 kHz a largely undisturbed mono reception is still possible.
The principle has been adopted in some high-end FM tuners like the analog Burmester Tuner 915 (1991)[19] or the digital synthesizer tuners Onkyo[nb 3] Integra T-4970 (1992)[16][2][3] and T-488F (1993)[15][20] as well as in various car radios, such as the Alpine 7619R (1989) and 1310R/3681 (1990),[17] the JVC KS-CG10 (1992),[4] the Clarion CRX121R (1993),[21] CRX123R (1993),[21] CRX121RM[22] and CRX123RM,[22] the Gelhard GXR 990S (1993) or the Conrad Soundcraft AR6800 DYNAS,[nb 4] which are particularly affected by difficult and rapidly changing reception conditions.
Similar technologies
The In Channel Select (ICS) system by H.u.C. Elektronik in 1984[5][23][24] is a DYNAS predecessor mainly for narrowband FM receivers.[25][26][27][28] It is based on the High Select tracking filter (German: Mitlauffilter aka MLF) developed by Jens Hansen since 1982.[5] ICS improved the selectivity by about 20 dB and the sensitivity by about 6 dB.[25]
A very similar technology is the Active Real-time Tracing System (ARTS), as was implemented in the Pioneer Elite F-91 and some versions of the F-717[nb 5] high-end tuners in 1987.[29][30][31][32][33]
Super Sound Tracing (SST) is a similar technology by Sony affecting the RF rather than the IF stage.[33][34][35] A four-stage SST system was implemented in high-end tuners such as the ST-S555ESX (1986), ST-S333ESX (1986), ST-S444ESX[36]/ST-S700ES (1987),[36] ST-S800ES (1987)[37] and ST-S333ESX II (1987)[38][36][39][34]/ST-S730ES (1988).[39][36] Advanced SST,[40][35] dividing the tuning range into 32 sections, was implemented in some model variants[nb 6] of the ST-S739ES, ST-S333ESG (1989)/ST-S770ES (1990)[36][41][35][40][42][nb 6] ST-S333ESA (1991), ST-S333ESJ (1993), ST-S707ES (1993)[36][43][44][nb 6] and ST-SA5ES (1994/1996).[45][36][nb 6]
Blaupunkt's Sharx technology, as introduced in 1997 in the Modena & Lausanne RD 148 car radios with "DigiCeiver", is a similar digital solution implemented in software. The original Sharx implementation still relied on a bank of switchable analog ceramic resonators for the IF filter stage before the A/D conversion for further processing of the signal in the DSP section. Around 2000, the switchable IF filter moved into the digital domain as well, that is, it was integrated into the DigiCeiver/TwinCeiver chip leaving only the first stage of the IF filter a discrete part.[46][47]
See also
- Körting Syntektor
- FM DX
- Frequency-following receiver
- Threshold extension demodulation
- Frequency demodulator using feedback or FM, FM feedback (FMFB)
Notes
- ^ Sources differ in regard to the exact founding date of Hansen's company from summer 1983[A] to 1984 to June 1985.[B]
- ^ While most sources state the company name as Hansen & Co., Hansen/Catito Elektronik, H&C Elektronik or H.u.C Elektronik GmbH, one source instead mentions a Berlin-based company named Sico-Elektronic GmbH which won the 1984 Berlin Innovation Prize for inventing an enhanced reception system for frequency-modulated radio signals.[C] (One of Hansen's patents was even filed by a company named "Sita Electronik GmbH" [sic].)
- ^ Some Onkyo product catalogs [1] seem to suggest that the Onkyo Integra T-9890DSR (1995) would support DYNAS as well, however, neither the user nor the service manual support this.
- ^ The Conrad Soundcraft AR6800 DYNAS car radio uses a TEMIC Tuner 1310 FAB 3X1 781 module. The unidentified DYNAS chip on the PCB is a glue-top chip on board (COB). [2][3][4]
- ^ Pioneer sold two completely different looking tuners under the F-717 name in 1987: The first one, labelled Digital Synthesizer Tuner F-717 on the front panel as sold in various international markets in 1987, is based on the F-77 (1985) tuner and does not support Active Real-time Tracing System (ARTS). [5][6] It was also sold as F-717L for a version with addition LW band capabilities. [7] The second one, labelled Reference Digital Synthesizer Tuner F-717 on the front, does support ARTS (also labelled as such on the front panel) and was sold at least in Japan in 1987. [8][9][10][11] This is a variant of the F-91 (1987) [12][13][14], but features an additional front panel switch to select from two FM antenna inputs at the back.
- ^ a b c d Super Sound Tracing (SST) was not implemented in all locale-specific model variants of these tuners. For example, according to the service manual,[D] in the UK, AEP, German and Italian versions of the ST-S770ES the real estate on the PCB for the SST circuitry was left unpopulated[E][F] and bypassed despite Sony advertising the tuner's SST feature in German product catalogs up to mid-1993.[G] A similar situation exists at least for the US, AEP, E, G and I variants of the ST-S707ES[H][I] [15][16] and some variants of the ST-SA5ES. [17][18] In the case of the ST-SA5ES even two vastly different PCB layouts exist: the first being very similar to the predecessor series (ST-S739ES/ST-S770ES/ST-S707ES and ST-S333ESG/ST-S333ESA/ST-S333ESJ), the second one a completely new design [19] (yet different from the successor ST-SA50ES).
References
- ^ a b c "U4292B - FM-IF IC for the DYNAS System" (PDF) (datasheet). A1 (preliminary ed.). Heilbronn, Germany: Telefunken Semiconductors / TEMIC TELEFUNKEN microelectronic GmbH . 1996-08-19. Archived (PDF) from the original on 2022-11-01. Retrieved 2021-06-07. p. 1:
The U4292B is a bipolar integrated FM-IF circuit, which is controlled by software. It performs all the functions of the DYNAS system. The device is designed for car radio and home receiver applications. DYNAS is a completely new system of FM-IF processing. It uses bandpass filters with a bandwidth down to about 20 kHz compared to 160 kHz for a conventional bandpass filter, and tracks the resonant frequency to the actual frequency. Implementation of the DYNAS system drastically enhances both of the basic, classic characteristics of radio reception: selectivity and reception sensitivity. DYNAS ensures enhancement up to levels which until now were not considered physically feasible.
Alt URL. - ^ a b c d e f Maier, Johannes (December 1992). F., K.; W., C. (eds.). "Volles Programm: Onkyo T 4970 - Der Goldwäscher für UKW". RadioExtrem. stereoplay (in German). Vol. 1992, no. 12. Stuttgart, Germany: Vereinigte Motor-Verlage . pp. 18–26 [20–21, 26]. ISSN 0172-388X. pp. 19–20:
Petsuya Toyama, Tunerentwickler von Onkyo [...] Dafür bietet der Newcomer sieben weitere hyperschmale Trennschärfepositionen an. Nach der von dem Berliner Jens Hansen ausgetüftelten Methode [...] stehen die entsprechenden, sich je nach Ernst der Empfangslage stufenweise mehr oder minder verengenden Türchen nicht mehr fest an einer Stelle. Damit die Musik-vermittelnden Frequenzauslenkungen noch durchpassen, versucht ihnen der Wackelschlitz so gut wie möglich zu folgen. Sobald der T 4970 Dynas-(Dynamic-Selectivity-)-Kunststückchen aufführen soll, wird die Zwischenfrequenz von 10,7 Megahertz noch einmal auf eine Lage um 700 Kilohertz umgesetzt. In härtesten UKW-Situationen versuchen dann gleich vier auf "scharf" gestellte, von elektronisch steuerbaren Kapazitätsdioden nachgezogene Schwingkreise den Modulationsschlenkern hinterherzuhechten. Die Abstimmspannung erzeugt sich der von der deutschen Firma Telefunken Electronics hergestellte Dynas-Chip dabei hintenrum, aus dem niederfrequenten Musik-Ausgangssignal. [...] Das klappt aber nur mit dem Mono-Summensignal perfekt, bei Stereo wüßte der arme [68-]beinige Siliziumkäfer ja nicht hü oder hott. Die wirksameren schmaleren Trennschärfetürchen kommen deshalb erst dann zum Einsatz, wenn es aufgrund der Feldstärke und bösartiger Frequenznachbarn ohnehin ratsam wird, auf die unkritische Mono-Wiedergabe umzuschalten. [...]
- ^ a b c d e f Wienforth, Ulrich (December 1992). "Imagepflege - Onkyo verteidigt seine Spitzenstellung: Tuner T-4970". Stereo (in German). pp. 28–31.
[...] Dann hilft nur noch jene Schaltung, die von einem Berliner Ingenieur entwickelt, von Telefunken als Chip realisiert und von Onkyo jetzt erstmals serienmäßig in einem Heimtuner eingesetzt wurde: Dynas. [...] Der Name steht für "Dynamic Selectivity", also dynamische Trennschärfe. Der Grundgedanke von Dynas ist, das konventionelle, statische Zwischenfrequenzfilter durch einen Mitlauffilter zu ersetzen, das den Frequenzänderungen des UKW-Signals folgt. Ein solches Filter kann entsprechend schmalbandiger sein und verbessert die Trennschärfe. Zusätzlich wird die Filterbandbreite je nach Stärke der störenden Nachbarsender in mehreren Stufen automatisch umgeschaltet. Dazu sind aufwendige Kontrollschaltungen notwendig, die aus dem Dynas-Chip einen veritablen Vielbeiner gemacht haben. [...]
- ^ a b c "5. Block Diagram & 6. Standard Schematic Diagram". JVC Service Manual - CD Changer Control Tuner Deck KS-CG10 B/E/G/GE/GI Digifine (revised G ed.). JVC. March 1992. pp. 1, 21–22. No. 49142. Archived from the original on 2021-06-14. Retrieved 2021-06-14. p. 1:
[...] DYNAS is a trademark of H.u.C. Ele[k]tronik GmbH [...] The DYNAS system has been modified from the intermediate system. Although the FM P.C. board and parts list are present, any FM adjustment procedure is not described. Until the FM adjustment method is published, therefore, the FM P.C. board should be replaced by the P.C. board ass'y. [...]
(NB. IC801 on the tuner PCB is a 68-pin U4290B.) - ^ a b c d e "Ungestörter Dialog mit tonangebender Technik". Neue Produkte. Tips Trends Märkte - Das Informationsblatt der Technologie-Vermittlungs-Agentur Berlin (in German). Vol. 1984, no. 2. Berlin, Germany: Technologie-Vermittlungs-Agentur (TVA). February 1984. Archived from the original on 2021-06-10. Retrieved 2021-06-10.
Wer hat sich nicht schon geärgert, wenn er beim Empfang seiner Lieblingssendung auf UKW in den entscheidenden Augenblicken durch überlagerte Nachbarsender gestört wurde. Ähnlich beklagenswert ist es für den Funkamateur, wenn der Empfang von der Großwetterlage abhängt und die atmosphärischen Störungen "Gewitterstimmung" verbreiten. [...] Nach dem Prinzip der Rauschunterdrückung versucht die Industrie daher seit Jahren, die Empfangsqualitäten von Radios und Funkgeräten entscheidend zu verbessern. Dolby und High Com sind Begriffe, mit denen dieses Prinzip bekannt wurde. [...] Für den Neuberliner Hansen und seinen Partner Müller-Catito ist die Leistungsfähigkeit dieser Verfahren auf die Dauer ungenügend. Um erheblich höhere Empfangsempfindlichkeiten und damit stark verbesserte Reichweiten zu erreichen, haben sie das Mitlauffilterverfahren (MLF) "High Select" entwickelt und sich damit selbständig gemacht. Mit diesem neuen Verfahren können Signale empfangen werden, die mit einem üblichen Empfänger nur noch als "Leerlaufrauschen" wahrnehmbar wären. [...] Die völlige Neuentwicklung benutzt anstelle eines in seiner Resonanzfrequenz feststehenden Zwischenfrequenzfilters ein schmalbandiges, in der Resonanzfrequenz steuerbares Filter, wobei die Steuerung dafür sorgt, daß der Filter-Resonanzbereich stets bei der Momentanzwischenfrequenz liegt. Das Ergebnis läßt sich hören. [...] Abschattungen, Reflexionsstörungen, Nachbarkanalstörungen in kritischen Versorgungsgebieten und Grenzempfindlichkeiten sind ausgeschaltet. Selbst völlig verrauschte Signale erklingen klar und deutlich. Die Realisierung des MLF-Verfahrens und die Gründung des eigenen Unternehmens sind das Ergebnis eines mehrjährigen Entwicklungsprozesses. 1982 kam der Erfinder Jens Hansen zur TVA und stellte seine Konzeption mit den durchgeführten grundlegenden Untersuchungen vor. Um den Nachweis der Realisierbarkeit anzutreten, mußte ein Funktionsmodell gebaut werden. Durch die Vermittlung der TVA wurde der Forschungsförderungsfonds des Senators für Wissenschaft und Forschung genutzt. [...] Für die Experten war das Konzept so überzeugend, daß es gefördert wurde. Ein Hochschullehrer der Technischen Fachhochschule Berlin ermöglichte Untersuchungen im Meßlabor. [...] Im Sommer 1983 konnten Hansen/Catito bereits das Funktionsmodell vorstellen, das die gewünschten Eigenschaften aufwies. [...] Dieser Erfolg ermutigte sie, selbst das neue Verfahren in marktfähige Produkte umzusetzen. Mit der TVA stimmten sie die nächsten Schritte ab. Die Unternehmensberatung für die Wirtschaft (ubw) wurde eingeschaltet, um im Rahmen des Förderprogramms "Existenzgründungsberatung" eine Unternehmenskonzeption auszuarbeiten. Mit der Unterstützung der TVA konnte die neue Firma Hansen/Catito Elektronik in das Berliner Innovations- und Gründerzentrum (BIG) einziehen. [...] Im Rahmen des Modellversuchs "Förderung technologieorientierter Unternehmensgründungen" wurde ein Antrag auf Förderung beim VDI TZ gestellt, um die Existenzgründer beim Aufbau eines eigenen Produktions- und Vertriebssystems zu unterstützen. [...] Hansen/Catito Elektronik - ein Beispiel für eine eindrucksvolle Initiative aus Berlin.
- ^ Freeman, Clive (1986-04-08). Written at Berlin, Germany. "High-Technology Investment Revitalizes Berlin - A Special Report on West Germany". International Herald Tribune - Published with the New York Times and The Washington Post. Vol. 15/86, no. 32,076. Paris, France. p. 12. ark:/13960/t88h3n32z. p. 12:
Two years ago, Jens Hansen, 42, a telecommunications engineer, won the Berlin Innovation Prize for inventing an enhanced reception system for frequency modulated signals. [...] Spurred by the award, he and Klaus Müller-Catito, a close colleague, launched H & C Electronics last June in the Ackerstrasse complex. His staff of seven produce accessory devices for radio systems, VHF units and satellite receiving systems. "We are small at present but growing rapidly," said Mr. Hansen, who formerly worked for Bosch in Berlin as a research engineer.
- ^ Ronzheimer, Manfred; Heller, Frank, eds. (2000-07-15) [1998]. "Innovationspreis Berlin-Brandenburg: Liste der Preisträger 1984–1994". Innovationspolitik (in German). BerliNews. Archived from the original on 2000-09-03.
[...] 1984 [...] System für die Erhöhung und Erweiterung der Frequenzmodulation im UKW-Bereich [...] Sico-Elektronic GmbH [...] Gustav-Meyer-Allee 25, 13355 Berlin [...] Herr Jens Hansen [...] Tel. 030/ 46 320 38, Fax 030/ 46 307 300 [...]
- ^ a b rotterle64 (2005-06-16) [2005-06-15]. "Re: "Scheunentor"-Empfänger schlägt Dynas". www.rundfunkforum.de (in German). Archived from the original on 2021-06-09. Retrieved 2021-06-10.
[...] es ein dynamischer ZF-Filter. Dynas ändert aber nicht nur seine Bandbreite[,] sondern auch seine Durchlaßfrequenz. Zuerst wird die ZF von 10,7 MHz auf 700 kHz heruntergemischt. Danach wird das Signal durch 4 LC-Kreise gefiltert [...] Durch zugeschaltete Widerstände können die LC-Kreise bedämpft werden[,] d.h. ihre Bandbreite wird größer. Mit diesen Filtern läßt sich eine Bandbreite bis [...] runter zu 10–15 kHz realisieren. Da diese Bandbreite nicht für UKW-Rundfunk reicht, müssen die Filter [...] nachgeregelt werden. Dies geschieht mittels Kapazitätsdioden. Die Steuerspannung dafür wird aus dem Mono-NF-Signal gewonnen. Dessen augenblicklicher Wert steht im direkten Zusammenhang mit der aktuellen Frequenz der ZF. Die Filter werden mit einer geringen Verzögerung nachgeführt. Ein normaler 85 kHz ZF-Filter dämpft einfach die Störungen[,] aber auch das Nutzsignal. Dynas hingegen läßt das Nutzsignal (Monosignal) komplett durch. Bei geringen NF-Pegeln grenzt es so die Störungen perfekt aus, bei hohen NF-Pegeln müssen die Filter so stark auslenken[, daß] auch Teile der Störfrequenzen mit durch kommen. Letztendlich hängt die Trennschärfe von Dynas also vom Programminhalt des Senders ab. Die heutige Dynamikkompression bei den Sendern ist da ungünstig für Dynas. [...] In einer Zeitschrift (AutoHifi), die [19]91/[19]92 herum Dynas noch als Prototyp vorstellte, stand drin, dass Dynas von einem ehemaligen Mitarbeiter von Blaupunkt, der eine eigene kleine Firma gegründet hatte, entwickelt bzw. heraus gebracht wurde. Die haben damals oder kurze Zeit später auch verschiedene Hersteller befragt[,] ob sie Dynas einsetzen wollen. [...]
{{cite web}}
: CS1 maint: numeric names: authors list (link) - ^ McLeod, Gordon Richard (January 1992) [1991-12-06]. "DYNAS-dynamic FM filter system". IEE Colloquium on Vehicle Audio Systems. London, UK: Institution of Engineering and Technology (IET): 4/1–4/3. S2CID 109889981.
The DYNAS system features an approach which many would consider to be physically impossible: the reception of a broadband transmission spectrum via narrowband filters. This principle seems self-contradictory at first consideration; at any rate, specialists could all easily agree that it does, however, satisfy many of the most critical needs and requirements actually encountered in receiving operations. The following are, of course, the advantages of broadband transmission: high signal-to-noise ratios, high dynamics, and a broad audio-frequency spectrum. The DYNAS principle would couple the above advantages with the following benefits of narrowband transmission: great reception sensitivity, and great immunity to interference. The DYNAS principle would, in addition, eliminate the following disadvantages: relative great susceptibility to interference, and poor signal quality. The above advantages, needs, and requirements are in fact implemented by DYNAS by the technique of dynamic selectivity.
[20] - ^ DYNAS system and its application in car radios (report). TEMIC Telefunken microelectronic . January 1992 [1989-12-14]. WO 89/12353 A1. (See also: WO89/12353)
- ^ "Das DYNAS-Empfangskonzept". radio fernsehen elektronik (rfe) (in German). Vol. 41, no. 2. Berlin, Germany: Verlag Technik GmbH / Huss-Medien GmbH . February 1992. pp. 88–90. ISSN 1436-1574. CODEN RFELB. (3 pages)
- ^ a b Herchner, Dieter (1997-04-24) [1993-09-25]. "Verfahren zur Steuerung eines FM-Empfängers mit nachführbarem ZF-Filter und Schaltungsanordnung zur Durchführung des Verfahrens" [Method for controlling an FM receiver with a trackable IF filter and circuit arrangement for carrying out the method] (in German and English). Heilbronn, Germany: TEMIC Telefunken Microelectronic GmbH . Patent DE4332767C2. Archived from the original on 2021-06-11. Retrieved 2021-06-10. [21][22]
- ^ Hansen, Jens (1993-12-15) [1989-05-30]. "FM-Empfangsteil" [FM receptor unit] (PDF) (in German, English, and French). Berlin, Germany: H.u.C. Elektronik GmbH. Patent EP0436542B1. WO 89/12353 (14.12.89 89/29). Archived (PDF) from the original on 2021-06-11. Retrieved 2021-06-08. [23][24] (36 pages) (See also: WO 89/12353 A1)
- ^ Rudolph, Dietmar (2009-01-31). "Das InChannelSelect Verfahren für UKW-FM". www.radiomuseum.org (in German). Archived from the original on 2021-06-10. Retrieved 2021-06-10. [25]
- ^ a b Onkyo Service Manual Synthesized FM Stereo/AM Tuner Model T-488F - Black and Silver models. Tokyo, Japan: Onkyo Corporation. pp. 3, 6–7, 10–11, 19–24 [10–11, 19, 21, 24]. Ref. No. 3441. PN0M3441 A209. Retrieved 2021-06-12. (26 pages) (NB. The 68-pin PLCC IC Q851 on U2, the Digital Circuit PCB (NADG-4605-1, 1A404505-1), of this tuner is a TEMIC U4290B (Onkyo Part. No. 22240641).
- ^ a b Onkyo Service Manual Synthesized FM Stereo/AM Tuner Model T-4970 - Black and Silver models. Tokyo, Japan: Onkyo Corporation. pp. 3, 6–7, 10–11, 19–24 [10–11, 19, 21, 24]. (26 pages) (NB. The 68-pin PLCC IC Q851 on U2, the Digital Circuit PCB (NADG-4605-1, 1A404505-1), of this tuner is a TEMIC U4290B.
- ^ a b Alpine Service Manual: Digital FM/MW/LW/RDS Tuner & CD Shuttle Controller 1310R. Alpine Electronics. pp. 24, 28. Retrieved 2021-06-12. (65 pages) (NB. The Alpine 1310R uses a 6-pin module FE002 (Part No. 77B50045W01), called DYNAS unit MB3R101A, which contains a U4290B chip (IC3001).)
- ^ a b c "Radio/Audio". TEMIC Integrated Circuits (PDF) (in English and Japanese). TOKO. pp. 56–57 [56]. Retrieved 2021-06-12. p. 56:
[...] U4290B-CP FM IF for Dynas System [...] U4291B-FP Coprocessor for Dynas [...] U4292B-FS Soft Dynas [...]
- ^ "Tuner Reviews A-C: Burmester 915 (1991)". Tuner Information Center. 2020 [2001]. Archived from the original on 2021-06-10. Retrieved 2021-06-10.
- ^ "Onkyo Tuners: Onkyo T-488F (1993) / Onkyo T-4970". Tuner Information Center. 2020 [2001]. Archived from the original on 2021-06-10. Retrieved 2021-06-10.
- ^ a b clarion Service Manual: RDS-EON/FM MPX/MW/LW Radio Cassette Combination With CD Changer Control Model CRX123R (PE-9806A) / CRX121R (PE-9825A). Tokyo, Japan: Clarion Co., Ltd., Service Information Section. pp. 2–3. Retrieved 2021-06-14.
- ^ a b clarion Service Manual CRX123RM / CRX121RM. Tokyo, Japan: Clarion Co., Ltd., Service Information Section. Retrieved 2021-06-14. (NB. The Clarion CRX121RM and CRX123RM utilize a 68-pin U2490B-B (IC601) on the main PCB.)
- ^ Hansen, Jens & Co. (20–21 September 1986). "In-Channel-Select-Verfahren". In Steger, Stefan & Bahner, Helmut (eds.). 31. Weinheimer UKW Tagung - Skriptum der Vorträge. UKW-Tagung Weinheim (in German). Vol. 31. Weinheim, Germany: Deutscher Amateur Radio Club e.V. (DARC) Ortsverband Weinheim / Funkamateur-Club Weinheim e.V. (FACW). pp. 84–90. (7 of 183 pages)
- ^ Schwarzbeck, Günter [in German]. "Verbesserung der Empfangseigenschaften von Schmalband-FM-Empfängern (ICS-Verfahren)" (PDF) (in German). Schönau-Altneudorf, Germany. Archived (PDF) from the original on 2021-04-11. Retrieved 2021-06-08. [26] (4+2 pages)
- ^ a b ICS - In-Channel-Select - das Empfangssystem der Zukunft / ICS-Restsignalverstärker (product flyer and manual) (in German). Berlin, Germany: H.u.C. Elektronik / Hansen & Co. Archived from the original on 2021-06-11. Retrieved 2021-06-11. (3+7 pages, page 6 missing)
- ^ Hawker, Pat, ed. (June 1987). "In-channel-select fm threshold extension". Technical Topics. RADio COMmunication (Radcom) - Journal of the Radio Society of Great Britain. 63 (6). Potters Bar, Herts, UK: Radio Society of Great Britain (RSGB): 406–412 [407]. ark:/13960/t9c58sk9x. p. 407:
Erwin David [...] draws attention to a short piece he wrote for the East Kent Radio Society's Carrier newsletter, based on an item by [Dick W. Rollema] in Electron November 1986. This describes a new "in-channel-select" (ics) technique that can significantly improve the sensitivity and selectivity of vhf/uhf fm receivers. A commercial "blackbox" adapter is being made and marketed by the German firm H&C Ele[k]tronik Hansen & Co of Berlin, which is claimed to improve the s:n ratio of weak fm signals by 6 dB and rejection of in-channel splatter from stronger adjacent-channel signals by some 20 dB. [...] the ics technique appears to be a form of threshold-extension demodulation, as originally developed for professional reception of weak satellite signals, but implemented in a form suitable for use with typical amateur radio fm transceivers. The German unit [...] features a very narrow voltage-controlled filter that automatically tracks the fm signal. For 145 MHz (25 kHz channelling) the filter bandwidth is only 1,800 Hz, ie about one-tenth of the usual i.f filter bandwidth. The receiver's fm detector output voltage, proportional to the instantaneous deviation, steers the ics filter so that it tracks the incoming signal. In demonstrations at a Dutch/German hamfest last year, [Rollema] reports that audibility of weak signals was improved by the unit from Q1 to Q4, though never completely to Q5. For strong signals it is usually advisable to switch threshold-extension demodulators out of circuit. The German hardware is being offered primarily as an external unit for base-station receivers, although the principle can be applied to mobile receivers. A threshold extension demodulator does not, of course, improve the front-end noise factor of a receiver, but there is no doubt that the technique does make it possible to copy signals that would otherwise be unintelligible. It certainly seems a development worth keeping in mind.
[27] - ^ Carlsson, Claes (September 1988). Written at Årby Fogdö, Strängnäs, Sweden. "ICS - Vad är det?" [ICS - What is that?] (PDF). QTC - Organ för Föreningen Sveriges Sändareamatörer (in Swedish). Vol. 60, no. 9. Farsta, Stockholm, Sweden: Föreningen Sveriges Sändareamatörer (SSA). pp. 416–417. ISSN 0033-4820. Archived (PDF) from the original on 2021-06-11. Retrieved 2021-06-11. (2 pages)
- ^ Hansen, Jens; Schwarzbeck, Günter [in German] (2008-01-05). Bopp, Matthias (ed.). "Das In-Channel-Select System" (PDF) (in German). Langenbrettach, Germany. Archived (PDF) from the original on 2021-04-11. Retrieved 2021-06-08. (1+3+6+6+1+13 pages) [28]
- ^ "11. Circuit description - 11.1. New IF system principle". F-91 FM/AM Digital Synthesizer Tuner - Service Manual (PDF) (in English, French, and Spanish). Tokyo, Japan / Long Beach, USA: Pioneer Electronic Corporation. August 1987. pp. 35–38 [37–38]. Order No. ARP1465. Archived (PDF) from the original on 2021-04-11. Retrieved 2021-06-10. p. 37:
[...] In the case of [the] conventional system, [the] signal pass[es] through the filter without generat[ing] distortion [...] filter is wide. At this time, the system is affected by undesired signal. In the case of [the] new system, [the] signal pass[es] through [...] [a] narrow filter follow[ing] the signal. [...] the system is not affected by undesired signal. This system's filter is controlled by feed[-]forward control, therefore, [the] stability is very high and [there is] no [...] oscillation. This system [implements a] follow[-]type filter so that [the] input FM signal frequency controlled for center of the filter at any time. ([In a] conventional system, [the] filter is followed the input signal.) [...] [The] system [...] consists of the control block and filter block. [The] control block [...] consists of [a] band pass filter [...], FM detector [...] and low-pass filter [...] The band-pass filter [...] has the same characteristic as conventional tuner's narrow filter, and this filter has selective characteristic sufficiently. When FM signal is inputed, FM signal is detected by FM detector [...] after pass through the band-pass filter [...] then, output signal of FM detector [...] is cut the useless high-frequency elements by low-pass filter [...] Filter block [...] consists of two mixer [...] band-pass filter [...] and VCO. Mixer [...] perform frequency change so that multiply input FM signal by VCO output. F-91 introduce the secondary IF frequency as 13.45 MHz. Band-pass filter [...] has the same narrow bandwidth characteristic as the band-pass filter [...] This filter (BPF2) cut the obstruction wave including input signal. Input signal of passed through the band-pass filter (BPF2) is multiplied by VCO output at mixer [...] again, then change to the original frequency. Original signal is detected by FM detector [...] then audio output is obtained. In this way, in spite of use the filter of fixed the center frequency, F-91 operate to the variable filter so that center frequency follow the input signal as equivalent. [...]
[29][30][31] (4 of 40 pages) - ^ Written at Tokyo, Japan. High-Fidelity Home-Entertainment - Audio & Video - Components & Systems (Exchange catalog for military). Germany: Pioneer Electronic Corporation / Pioneer Electronic GmbH. June 1987. 50,000-KL(F)280-6-87. Archived from the original on 2021-06-09. Retrieved 2021-06-11 – via Deutsches Hi-Fi-Museum.
[...] ARTS Cleans Up Your Act [...] Pioneer's new Active Real-Time Tracing System - ARTS for short - helps the F-91 deliver clean and optimum signal reception. It replaces the "WIDE/NARROW" filtering technique in which the WIDE position provided better sound quality at the expense of selectivity and, conversely, the NARROW position provided better selectivity at the expense of sound quality (see oscillophotos). Using a kind of "servo-filtering", its IF filter circuit "tracks" the tuned frequency in real time, eliminating interference ONLY where it actually exists, thus providing optimum sound quality AND selectivity. [...] F-91 - Reference Digital Synthesizer Tuner [...] Pioneer's ARTS (Active Real-Time Tracing System): Tuned frequency is followed in real time by IF filter circuit to eliminate interference and pass on purest possible signal to audio output. [...]
- ^ Feldman, Leonard (August 1988). "Pioneer Elite F-91 Tuner" (PDF). Audio (review). Hachette Filipacchi Media U.S. pp. 58–60, 62, 67 [59]. Archived (PDF) from the original on 2019-04-19. Retrieved 2021-06-10. p. 59:
[...] an FM i.f. circuit that has been given the acronym ARTS (for Active Real-time Tracing System). This system eliminates the need for choosing between narrow and wide i.f. bandwidths. Pioneer states that it actively follows the selected signal to provide both the lower distortion normally resulting from wide bandpass and the high selectivity of narrow bandpass. I gathered that the system dynamically tailors bandwidth to the instantaneous modulation of the incoming signal. [...] I also saw evidence that the r.f. section has some capability of tracking the signal; even when my FM signal generator was deliberately detuned from the frequency indicated on the F-91's display, minimum distortion and perfect center tuning were maintained. [...]
- ^ "Pioneer Tuners: Pioneer F-91 (1987)". Tuner Information Center. 2020 [2001]. Archived from the original on 2021-04-11. Retrieved 2021-06-10.
- ^ a b Rich, David Arthur; Modafferi, Richard Thomas (Winter 1995–1996). "FM Tuners: The Present State of the Art of FM Reception" (PDF). The Audio Critic. No. 23. Quakertown, Pennsylvania, USA: Critic Publications, Inc. pp. 43–64 (PDF:39–56) [56 (PDF:48)]. ISSN 0146-4701. 0-74470-82057-4-51. Archived (PDF) from the original on 2011-07-16. Retrieved 2021-06-10. pp. 56–57 (PDF:48–49):
[...] Pioneer came up with a very innovative solution to the "narrow filters distort the signal" problem. They used this solution in the F-91 tuner. It is such a good idea that it could have gotten someone a Ph.D. (Indeed, a related concept did get someone a Ph.D.—see [Rich 1991].) What the engineers at Pioneer observed was that, although the spectrum of an FM signal is wide when averaged over time, at any instant in time the signal has just one spectral line at the instantaneous frequency. So, if you build a time-varying filter with a very narrow band-width that moves with the instantaneous frequency of the desired signal, then you can eat your cake and have it too. The very narrow bandwidth removes the interferers, but the time-varying nature of the filter insures that the FM signal is not distorted. To move the filter around, a complete auxiliary IF strip designed in the conventional manner and a PLL FM detector are required. We now have a chicken and egg problem, since the conventional receiver has to place the passband of the time-varying filter in the correct place. This is what limits the performance of the system. One very interesting (at least to this author) variation on this is to replace the bandpass filter with a notch filter. Then the stronger signal is removed, but a weaker cochannel interfering signal may now be revealed. Further information on this is in—you guessed it—[Rich 1991]. [...] Sony uses a variation on the tracking-filter theme that involves dynamically varying the position of the RF and mixer filters in response to the signal level at the output of the FM demodulator (which represents how far the instantaneous frequency has moved from the carrier frequency). This is easier to implement in the RF and mixer stages than in the IF because these filters are already tunable. One would think the large signal delay in the IF strip and detector would prevent this from working well, but Sony is shipping tuners with this thing, so it must do something positive. [...]
- ^ a b "ST-S333ESXII: Superior Reception of FM Signals". FM Stereo/AM Tuners (product catalog). Sony. Archived from the original on 2021-06-16. Retrieved 2021-06-16.
[...] SST (Super Sound Tracing) Significantly Improves Filter Characteristics [...] The task of the front end of an FM tuner is to capture the desired frequency with accuracy and without interference. Interference can be more efficiently eliminated by narrowing the bandwidth of a filter and by sharpening its curve. In the front end, tracking error occurs when there is a discrepancy between the frequency of the broadcast station and the center of the band-pass filter. A narrower band-width, such as the ST-S333ESXII's, allows less margin for this sort of error and improves selectivity. Previously, it was difficult to [achieve] accurate reception throughout the FM band, because FM broadcast frequencies fluctuate with the strength of their signal. If the FM frequency reception is perfectly adjusted on both ends of a bandwidth - that is, at 87.5 MHz and 108 MHz - an error of up to 100 kHz will occur when attempting to receive frequencies broadcast between these points. Likewise, if the FM frequency reception is perfectly adjusted at the center of the bandwidth, error will occur at either end. S.S.T. Circuitry effectively solves this problem. With the ST-S333ESXII's frequency range divided into four separate sections between 87.5 MHz and 108 MHz, perfect frequency reception can be [achieved] at each of these points, and the error occurring between them is effectively minimized. You'll enjoy better FM selectivity, less tracking error and less distortion, thanks to the S.S.T. Circuitry. [...] WOIS - Wave Optimized IF System [...] The WOIS automatically selects the ideal IF characteristics for both the monaural and stereo positions at the IF Filter stage. The results are system selectivity of 65 dB and THD (Total Harmonic Distortion) minimized at 1 kHz to 0.005% in mono and 0.0095% in stereo. This sophisticated technology has been integrated to create overall sound quality that is noticeably better. [...]
- ^ a b c "Großer Empfang. Sonys Tuner-Technik". SONY Programm '92 (in German). Cologne, Germany: Sony Deutschland GmbH. March 1992. pp. 130–132. p. 130:
[...] WOIS (ZF mit optimierter Filtercharakteristik) [...] Um eine optimale Signalverarbeitung zu gewährleisten, sind für Mono- und Stereo-Rundfunksignale unterschiedliche Filtercharakteristiken im Zwischenfrequenzverstärker erforderlich. Die WOIS-Technik selektiert automatisch die entsprechende Charakteristik und sorgt so bei Stereo- und Mono-Empfang für die jeweils optimale Selektivität, d.h., daß auch eng benachbarte Sender sauber voneinander getrennt werden. Das verbesserte Gruppenlaufzeitverhalten und das linearisierte Amplitudenverhalten reduzieren die Verzerrungen und tragen zur Klangoptimierung bei. [...] SST (Super Sound Tracing) [...] Die wichtigste Anforderung an einen Tuner ist der präzise Empfang der jeweils eingestellten Frequenz. Sonys SST-Technik stellt die Bandbreite der Eingangsstufe exakt auf die Empfangsfrequenz ein und verbessert so die Trennung des Nutzsignals von störenden benachbarten Senderfrequenzen. Diese verbesserte Vorselektion sorgt für störungsfreien Empfang. [...]
(218 pages + technical data and pricelist inlays) (NB. This 1992 product catalog describes the SST technology, and explicitly lists SST as a feature of the ST-S770ES, but also shows a photo of an opened ST-S770ES where the "Advanced SST" section is unpopulated on the PCB. While the 1993 catalog no longer describes SST, it is still listed as a feature of the ST-S770ES, until the tuner was replaced by its successor model, the ST-S707ES, in the subsequent 1993/1994 catalog.) - ^ a b c d e f g "Sony Tuners: Sony ST-S333ESXII / Sony ST-S444ESX / Sony ST-S500ES (1987) / Sony ST-S700ES(1987) / Sony ST-S707ES (1995) / Sony ST-S730ES (1988) / Sony ST-SA5ES (1996)". Tuner Information Center. 2020 [2001]. Archived from the original on 2021-06-09. Retrieved 2021-06-10.
- ^ Sony ST-S800ES Service Manual - AEP Model / G-AEP Model (PDF) (in English, French, and German). Sony. Archived (PDF) from the original on 2019-12-31. Retrieved 2021-06-12.
- ^ "SONY ST-S333ESXII". nice.kaze.com (in Japanese). 2006-03-18. Archived from the original on 2021-06-10. Retrieved 2021-06-10.
- ^ a b Sony Service Manual FM Stereo/FM-AM Tuner ST-S333ESXII/ST730ES - US Model, AEP Model, UK Model / E Model (in English, French, and German). Sony Corporation, Audio Group, A/V Engineering Service Department. 9-953-824-11. Retrieved 2021-06-12. (34 pages)
- ^ a b jomol (2020-01-31). "SONY ST 770 Tuner: SST nachrüsten?". hifi-forum.de (in German). Retrieved 2021-06-12. [32][33]
- ^ "Photo of German Sony ST-S770ES PCB". Retrieved 2021-06-12.
- ^ Service Manual FM Stereo / FM-AM Tuner ST-S770ES - AEP Model / UK Model. Sony Corporation, Audio Group / Customer Relations and Service Group. September 1991. pp. 8–9, 11, 18–23 [18–19, 21]. 9-956-628-11. 91I0850-1. (40 pages) (NB. This service manual, which covers the UK, AEP, German and Italian model variants shows PCBs and schematics with SST not populated.)
- ^ Sony Service Manual FM Stereo/FM-AM Tuner ST-S707ES - AEP Model, E Model, G Model, I Model (in English, French, and German). Retrieved 2021-06-16. (NB. These model variants do not implement SST.)
- ^ Sony Service Manual FM Stereo/FM-AM Tuner ST-S707ES - US Model (in English, French, and German). Archived from the original on 2021-06-16. Retrieved 2021-06-16. (NB. This model variant does not implement SST.)
- ^ "SONY ST-SA5ES". nice.kaze.com (in Japanese). 2008-02-14. Archived from the original on 2021-04-11. Retrieved 2021-06-10.
- ^ "DigiCeiver: Blaupunkt car audio delivered carriage-free to your home - Blaupunkt digiceiver technology". Blue Spot Car Audio. Blaupunkt. 2000. Archived from the original on 2000-01-26.
- ^ "Blaupunkt car audio delivered carriage-free to your home - DigiCeiver technology". Blaupunkt. 2009-07-08. Archived from the original on 2009-07-08.
Further reading
- U4290B (datasheet). Heilbronn, Germany: Telefunken Semiconductors / TEMIC TELEFUNKEN microelectronic GmbH .
- U4291B (datasheet). Heilbronn, Germany: Telefunken Semiconductors / TEMIC TELEFUNKEN microelectronic GmbH .
- Rudolph, Dietmar (2016-11-09). "FM-Demodulation: weniger bekannte Verfahren - FM Radios mit Frequenz-Gegenkopplung". Radiomuseum (in German). Archived from the original on 2021-06-14. Retrieved 2021-06-14.
- "FM-ZF-Filter: In-Channel-Select (ICS)" [FM IF filter: In Channel Select (ICS)]. Funkschau (in German). Vol. 58, no. 14. Munich, Germany: Franzis-Verlag GmbH. 1986-07-04. pp. 35–. ISSN 0016-2841.
- Hansen, Jens (December 1991). "In der Spur des Nutzsignals". Funkschau (in German). Vol. 63, no. 25. Munich, Germany: Franzis-Verlag GmbH / WEKA Holding . pp. 74–77. ISSN 0016-2841.
- "(unknown)". Autohifi (in German). Weka Media Publishing GmbH . 1991.
{{cite magazine}}
: Cite uses generic title (help) - "(unknown)". stereoplay (in German). Vol. 1991, no. 7. Stuttgart, Germany: Vereinigte Motor-Verlage . July 1991. ISSN 0172-388X.
{{cite magazine}}
: Cite uses generic title (help) - "(unknown)". CQ DL. Vol. 58, no. 11. Deutscher Amateur Radio Club e.V. (DARC). November 1986. pp. inlet 18–19. ISSN 0178-269X.
{{cite magazine}}
: Cite uses generic title (help) - "(unknown)". CQ DL. Vol. 59, no. 1. Deutscher Amateur Radio Club e.V. (DARC). January 1987. pp. 6–9. ISSN 0178-269X.
{{cite magazine}}
: Cite uses generic title (help) - Rollema, Dick W. (November 1986). "(unknown)". Electron (in Dutch). Vol. 41, no. 11. Vereniging voor Experimenteel Radio Onderzoek Nederland (VERON). ISSN 0013-4767.
{{cite magazine}}
: Cite uses generic title (help) - David, Erwin (1986–1987). "(unknown)". Carrier. East Kent Radio Society (EKRS).
{{cite news}}
: Cite uses generic title (help) - Bell, David Arthur (1942-11-01) [August 1942]. "Reduction of Band Width in F.M. Receivers" (PDF). Wireless Engineer - The Journal of Radio Research & Progress. XIX (230). London, UK: A. C. Cossor Limited, Research Department / Iliffe & Sons Ltd. : 497–502. ISSN 0268-6465. OCLC 183317383. Archived (PDF) from the original on 2021-03-09. Retrieved 2021-06-16. p. 497:
This paper discusses the possibility of using a high degree of negative feed-back of frequency modulation in the I.F. section of a frequency modulation receiver, for the purpose of (a) minimising the necessary I.F. band width and (b) making the detected output independent of amplitude without the use of an amplitude-limiter in the I.F. amplifier.
(6 pages) - Panter, Philip F. (1965). Modulation, Noise, and Spectral Analysis: Applied to Information Transmission (1 ed.). New York, USA: McGraw-Hill Book Co., Inc. ISBN 0-07048446-5. OCLC 565424. S2CID 106666863. ISBN 978-0-07048446-7. (viii+750+9+v pages)
- Nyquist, Harry. (unknown). British Patent No. 531779.
{{cite book}}
: Cite uses generic title (help) - Carson, John Renshaw (1939-07-03). "Frequency-Modulation: Theory of the Feedback Receiving Circuit". Bell System Technical Journal. 18 (3): 395–403. doi:10.1002/j.1538-7305.1939.tb03584.x. ISSN 0005-8580. ark:/13960/t51g21662. Retrieved 2021-06-16. (9 pages) [34]
- Chaffee, Joseph G. (1939-07-03). "The Application of Negative Feedback to Frequency-Modulation Systems". Bell System Technical Journal. 18 (3): 404–437. doi:10.1002/j.1538-7305.1939.tb03585.x. ISSN 0005-8580. S2CID 51659322. ark:/13960/t3qv4v85m. Retrieved 2021-06-16. (34 pages) [35]; Chaffee, Joseph G. (May 1939). "The Application of Negative Feedback to Frequency-Modulation Systems". Proceedings of the I.R.E. 27 (5): 317–331. doi:10.1109/JRPROC.1939.228396. ISSN 0096-8390. OCLC 1753246. S2CID 109993045. Retrieved 2021-06-16. (15 pages) (NB. Presented before the New York Section of the I.R.E. on 1939-05-03.)
- Chaffee, Joseph G. (1937-03-30) [1936-03-26]. Written at Hackensack, New Jersey, USA. "Reception of frequency modulated waves". New York, USA: Bell Telephone Laboratories, Incorporated. Patent US2075503. Retrieved 2021-06-16. (7 pages) [36]
- Roberts, J. H. (November 1968). "Dynamic tracking filter as a low-threshold demodulator in f.m. f.d.m. satellitesystems". Proceedings of the Institution of Electrical Engineers. 115 (11): 1597–1606. doi:10.1049/piee.1968.0280. ISSN 0020-3270.
- Roberts, J. H. (November 1968). "Frequency-feedback receiver as a low-threshold demodulator f.m. f.d.m. satellite systems". Proceedings of the Institution of Electrical Engineers. 115 (11): 1607–1618. doi:10.1049/piee.1968.0281. ISSN 0020-3270.
- Papoulis, Athanasios (1962). The Fourier Integral and its Applications. New York, USA: McGraw-Hill Book Company. pp. 94–109. LCCN 62-10211. SBN 07-048447-3.
- Oppenheim, Alan Victor; Schafer, Ronald W. (1975). Digital Signal Processing. Englewood Cliffs, New Jersey, USA: Prentice-Hall. pp. 155–160. ISBN 0-13-214107-8.
- FR8121986A
- Hansen, Jens (1984-03-07) [1983-03-30, 1981-09-23]. "Filter- und Demodulationsschaltung" (in German). Robert Bosch GmbH. Patent EP0075071A3. Retrieved 2021-06-12.
- Hansen, Jens (1986-04-03) [1981-12-01]. "Filter- und Demodulationsschaltung" (in German and English). Robert Bosch GmbH. Patent DE3147493A1. Retrieved 2021-06-12.
- Hansen, Jens (1986-04-17) [1984-10-16]. "Verfahren und Schaltungsanordnung zum Umsetzen frequenzmodulierter Signale über mindestens eine Zwischenfrequenz in Niederfrequenzsignale" (in German). Berlin, Germany: Hansen Catito GmbH / H.u.C. Elektronik GmbH. Patent DE3438286A1. Archived from the original on 2021-06-11. Retrieved 2021-06-11.
- Hansen, Jens (1988-12-01) [1987-04-15]. "Anordnung zum Filtern eines FM-UKW-Empfangssignals" [Arrangement for filtering an FM VHF reception signal] (in German and English). Berlin, Germany: H.u.C. Elektronik GmbH. Patent DE3724604A1. Archived from the original on 2021-06-11. Retrieved 2021-06-11.
- Hansen, Jens (1994-12-14) [1987-04-15]. "Anordnung zum Filtern eines FM-Empfangssignals" [Arrangement for filtering an incoming FM signal] (in English, German, and French). Berlin, Germany: H.u.C. Elektronik GmbH. Patent EP0358649A1/EP0358649B1. Retrieved 2021-06-12. [37][38]
- Hansen, Jens (1994-12-14) [1988-10-20, 1987-04-15]. "Anordnung zum Filtern eines FM-Empfangssignals" [Arrangement for filtering an incoming FM signal] (in German, English, and French). Berlin, Germany: H.u.C. Elektronik GmbH. Patent WO1988008223A1. Retrieved 2021-06-12. [39]
- Hansen, Jens (1992-10-27) [1987-04-15]. "Arrangement having tracking IF filter". Berlin, Germany: H.u.C. Elektronik GmbH. Patent US5159709. Retrieved 2021-06-12. [40]
- Hansen, Jens (1989-12-07) [1988-05-30]. "FM-Empfangsteil" [FM receiver] (in German and English). Berlin, Germany: H.u.C. Elektronik GmbH. Patent DE3818751A1. Retrieved 2021-06-12.
- Hansen, Jens (1989-12-14) [1988-05-30]. "FM-Empfangsteil" [FM receiver] (in German and English). Berlin, Germany: H.u.C. Elektronik GmbH. Patent DE3818750A1. Retrieved 2021-06-11.
- Hansen, Jens (1994-11-29) [1988-05-30]. "FM receiver which detects and responds to receiving and interference states". Berlin, Germany: H.u.C. Elektronik GmbH. Patent US5369470A. Archived from the original on 2021-06-10. Retrieved 2021-06-11. [41]
- Terman, Frederick E. (2020-04-03). "AC voltmeter afregelen FM tuner". Circuits Online (in Dutch). Stichting Circuits Online. Archived from the original on 2021-06-11. Retrieved 2021-06-11.
- http://antique-autoradio-madness.org/alpine/Alpine-1989/alpine-1989-cata_4.htm
- https://www.fmtunerinfo.com/ST-SA5service.pdf (Describes the old PCB layout in a model variant without SST populated.)
- https://patentimages.storage.googleapis.com/8d/fc/40/37ed83234d8c81/US4293818.pdf
- Rich, David Arthur (January 1991). Cochannel FM interference cancellation using adaptive notch filters (Ph.D. dissertation). Brooklyn, New York, USA: Polytechnic University. UMI Order Number GAX91-17490.
- Asbrink, Leif (2017-12-26). "My, that's a heavy little box!". Archived from the original on 2021-06-16. Retrieved 2021-06-16.
- Großklaß, Stephan (2011) [2008-05-15]. "Receiver Concepts for Dummies - Background on mediumwave, shortwave and FM receivers". Archived from the original on 2021-06-12. Retrieved 2021-06-12.
- https://www.rundfunkforum.de/viewtopic.php?t=15593
- Warren, Rich (1988-03-11). "Citation 23 Tuner - A Sherlock at tracking radio stations". Chicago Tribune. Retrieved 2021-06-11.
- "Harman/Kardon TU920 Tuner". HiFi Review. Archived from the original on 2021-06-11. Retrieved 2021-06-11.