Editing Intermediate frequency (section)

==References==
{{reflist|refs=
<ref name="Malanowski_2011">{{cite book |author-last=Malanowski |author-first=Gregory |title=The Race for Wireless: How Radio Was Invented (or Discovered?) |publisher=Authorhouse |date=2011 |page=69 |url=https://books.google.com/books?id=IAjtEeVtXqAC&q=superheterodyne&pg=PA69 |isbn=978-1-46343750-3}}</ref>

<ref name="Pioneer_1987">{{cite book |title=F-91 FM/AM Digital Synthesizer Tuner - Service Manual |chapter=11. Circuit description - 11.1. New IF system principle |language=en, fr, es |publisher=[[Pioneer Electronic Corporation]] |publication-place=Tokyo, Japan / Long Beach, USA |id=Order No. ARP1465 |date=August 1987 |pages=35–38 [37–38] |url=https://fmtunerinfo.com/F-91service.pdf |access-date=2021-06-10 |url-status=live |archive-url=https://web.archive.org/web/20210411023352/https://fmtunerinfo.com/F-91service.pdf |archive-date=2021-04-11 |quote-page=37 |quote=[…] Mixer […] perform frequency change so that multiply input FM signal by [[Voltage-controlled oscillator|VCO]] output. F-91 introduce the secondary IF as 13.45&nbsp;MHz. Band-pass filter […] has the same narrow bandwidth characteristic as the band-pass filter […] Input signal […] passed through the band-pass filter […] is multiplied by VCO output at mixer […] then change[d] to the original frequency. Original signal is detected by FM detector […] audio output is obtained. […] 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. […]}}[https://web.archive.org/web/20210411023407/https://www.fmtunerinfo.com/F-91ARTS.pdf][https://web.archive.org/web/20200114001025/http://nice.kaze.com/av/f-91_svm.pdf] (4 of 40 pages) (NB. The ''Pioneer Elite F-91'' and the very similar ''Pioneer Reference Digital Synthesizer Tuner F-717'' (as sold in Japan) supported [[Active Real-time Tracing System]] (ARTS) in 1987, whereas the completely different but almost identically named ''Pioneer Digital Synthesizer Tuner F-717'' and ''F-717L'' (as sold internationally in 1987) were based on the F-77 and did not support ARTS.)</ref>

<ref name="Telefunken_1996">{{cite web |title=U4292B - FM-IF IC for the DYNAS System |type=datasheet |edition=preliminary |publisher={{ill|Telefunken Semiconductors|de}} / {{ill|TEMIC{{!}}TEMIC TELEFUNKEN microelectronic GmbH|de|TEMIC}} |location=Heilbronn, Germany |date=1996-08-19 |version=A1 |url=http://pdf.datasheetcatalog.com/datasheet/Temic/mXyzurwy.pdf |access-date=2021-06-07 |url-status=live |archive-url=https://web.archive.org/web/20200315134551/http://datasheetcatalog.com/datasheets_pdf/U/4/2/9/U4292B.shtml |archive-date=2020-03-15 |quote-page=1 |quote=[…] [[DYNAS]] system […] for car radio and home receiver applications […] system of [[frequency modulation|FM]]-IF processing […] [[bandpass filter]]s with a [[frequency bandwidth|bandwidth]] down to about 20&nbsp;kHz compared to 160&nbsp;kHz for a conventional […] filter […] tracks the [[resonant frequency]] to the actual frequency […]}} [https://web.archive.org/web/20210611182301/https://www.circuitsonline.net/forum/file/53516] (13+1 pages)</ref>

<ref name="Hansen_ICS">{{cite book |title=ICS - In-Channel-Select - das Empfangssystem der Zukunft / ICS-Restsignalverstärker |language=de |type=product flyer and manual |publisher=H.u.C. Elektronik / Hansen & Co. |date= |publication-place=Berlin, Germany |url=https://www.circuitsonline.net/forum/file/53580 |access-date=2021-06-11 |url-status=live |archive-url=https://web.archive.org/web/20210611182422/https://www.circuitsonline.net/forum/file/53580 |archive-date=2021-06-11}} (3+7 pages, page 6 missing)</ref>

<ref name="Electra_Bearcat">Electra Bearcat scanner radios</ref>

<ref name="Army_1952">{{cite book |title=Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers |publisher=[[US Department of the Army]] |date=1952 |pages=195–197 |url=https://books.google.com/books?id=f9QXAAAAYAAJ&pg=PA195}}</ref>

<ref name="Rembovsky_2009">{{cite book |author-last1=Rembovsky |author-first1=Anatoly |author-last2=Ashikhmin |author-first2=Alexander |author-last3=Kozmin |author-first3=Vladimir |title=Radio Monitoring: Problems, Methods and Equipment |publisher=Springer Science and Business Media |date=2009 |pages=26 |url=https://books.google.com/books?id=2ra1lg9MCLgC&q=selectivity+sensitivity+image&pg=PA26 |isbn=978-0387981000 |display-authors=etal}}</ref>

<ref name="Langford-Smith_1941">{{cite book |title=Radiotron Designer's Handbook |chapter=Chapter 15. Frequency conversion: The principle of the Superheterodyne / Chapter 17. Intermediate Frequency Amplifiers: Choice of Frequency |editor-first=Fritz |editor-last=Langford-Smith |editor-link=Fritz Langford-Smith |edition=4th impression, 3rd |publisher=[[Wireless Press]] for [[AWA Technology Services|AWA]] / [[RCA]] |publication-place=Sydney, Australia / Harrison, New Jersey, USA |date=November 1941 |orig-date=1940 |pages=90, 99–100, 104, 158–159 [100, 159] |url=https://pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_51/4394_Radiotron_Designers_Handbook_3rd_Ed.pdf |access-date=2021-07-10 |url-status=live |archive-url=https://web.archive.org/web/20210203003154/https://www.pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_51/4394_Radiotron_Designers_Handbook_3rd_Ed.pdf |archive-date=2021-02-03 |quote-pages=100, 158–159 |quote=[…] it can be assumed that the desired intermediate frequency is 465&nbsp;[[kilohertz|Kc/s]] […] for this reason frequencies in the region of 450–465&nbsp;Kc/s are very widely used […] [[Superheterodyne receiver]]s, designed specifically for short-wave communication work, usually have a higher frequency for the I.F., from about 1,600 to 3,000&nbsp;Kc/s, and may also incorporate double frequency changing. For example the receiver may change the incoming signal first to 3,000&nbsp;Kc/s and then to 465&nbsp;Kc/s or lower. […] Various frequencies are used for the I.F. amplifiers of radio receivers. A frequency of 110&nbsp;Kc/s. has been used widely in Europe where the [[long wave band]] is in use. This gives extremely good selectivity but serious side band cutting. A frequency of 175&nbsp;Kc/s. has been used for broadcast band reception both in America and Australia for a number of years but its use on the [[short-wave band]] is not very satisfactory. A frequency in the region on 250–270&nbsp;Kc/s. has also been used to a limited extent as a compromise between 175 and 465&nbsp;Kc/s. The most common frequencies for dual wave receivers are between 450 and 465&nbsp;Kcs.[…] and, particularly if iron cored I.F. transformers are used, this frequency band is a very good compromise. For short-wave receivers which are not intended for operation at lower frequencies, an intermediate frequency of 1,600&nbsp;Kc/s. or higher may be used. […] A frequency of 455&nbsp;Kc/s. is receiving universal acceptance as a standard frequency, and efforts are being made to maintain this frequency free from radio interference. […]}} (See also: [[Radiotron Designer's Handbook]])</ref>

<ref name="Langford-Smith_1953">{{cite book |editor-first=Fritz |editor-last=Langford-Smith |editor-link=Fritz Langford-Smith |author-first1=Bill |author-last1=Sandel<!-- (1917-) --> |author-first2=Ian C. |author-last2=Hansen |display-authors=etal |title=Radiotron Designer's Handbook |chapter=Chapter 26. Intermediate Frequency Amplifiers. Section 1. Choice of Frequency (ii) Commonly accepted intermediate frequencies / Section 2: Number of stages / Chapter 34. Types of A-M Receivers. Section 2: The Superheterodyne / Chapter 38. Tables, Charts and Sundry Data. Section 4. Standard Frequencies (iii) Standard Intermediate Frequencies |edition=4 |publisher=[[Wireless Press]] for [[AWA Technology Services|AWA]] / [[RCA]], Electron Tube Division |publication-place=Sydney, Australia / Harrison, New Jersey, USA |date=January 1960 |orig-date=1953, 1952, 1940, 1935, 1934 |pages=1021–1022, 1226, 1293–1295, 1361 |url=http://www.tubebooks.org/books/rdh4.pdf |access-date=2021-07-09 |url-status=live |archive-url=https://web.archive.org/web/20210708135027/http://www.tubebooks.org/books/rdh4.pdf |archive-date=2021-07-08 |quote-pages=1021–1022, 1226, 1361 |quote=[…] As a result of the experience gained over a number of years in addition to the considerations stated previously the values selected for the intermediate frequencies of most commercial receivers have become fairly well standardized. For the majority of broadcast receivers tuning the bands 540–1600&nbsp;[[kilohertz|Kc/s]] and 6–18&nbsp;[[megahertz|Mc/s]], an i-f of about 455&nbsp;Kc/s is usual. A frequency of 110&nbsp;Kc/s has been extensively used in Europe where the [[long wave band]] of 150–350&nbsp;Kc/s is in operation. Receivers for use only on the [[short wave band]] commonly the 40–50&nbsp;Mc/s band generally use a 4.3&nbsp;Mc/s i-f, and for the 88–108&nbsp;Mc/s band they use 10.7&nbsp;Mc/s. This latter value has been adopted as standard in U.S.A., and some other countries, for [[Very high frequency|v-h-f]] receivers. […] Short wave receivers using 1600&nbsp;Kc/s i-f transformers commonly employ two stages (3 transformers) although one stage is often used […] In wide band and communication receivers, two or more stages are commonly used. The intermediate frequency in general use is 455&nbsp;Kc/s. Earlier receivers used 175&nbsp;Kc/s but with the appearance of powdered iron cores and the development of high slope amplifier valves, the previous objection to the use of higher intermediate frequencies, i.e. lower gain, was nullified. […] It is recommended that [[superheterodyne receiver]]s operating in the [[medium frequency]] [[broadcast band]] use an intermediate frequency of 455&nbsp;Kc/s. This frequency is reserved as a clear channel for the purpose in most countries of the world. […] The European "[[Copenhagen Frequency Plan of 1948|Copenhagen Frequency Allocations]]" provide the following two intermediate frequency bands: 415–490&nbsp;Kc/s and 510–525&nbsp;Kc/s. […] An intermediate frequency of 175&nbsp;Kc/s is also used. […] The American [[Radio Television Manufacturers Association|RTMA]] has standardized the following intermediate frequencies (REC-109-B, March 1950): Standard broadcast receivers&mdash;either 260 or 455&nbsp;Kc/s. V-H-F broadcast receivers&mdash;10.7 Mc/s.}} [https://web.archive.org/web/20210709230051/https://worldradiohistory.com/BOOKSHELF-ARH/Handbooks/Radiotron-Designer%27s-Handbook-4th-Edition.pdf][https://archive.org/details/bitsavers_rcaRadiotr1954_94958503] (See also: [[Radiotron Designer's Handbook]])</ref>

<ref name="Dixon_1998">{{cite book |author-last=Dixon |author-first=Robert |title=Radio Receiver Design |publisher=[[CRC Press]] |date=1998 |pages=57–61 |url=https://books.google.com/books?id=hqkKAV1KsrQC&pg=PA57 |isbn=0-82470161-5}}</ref>
<ref name="Hayward_1977">{{cite book |author-first=Wes |author-last=Hayward |editor-first=Doug |editor-last=De Maw |title=Solid state design for the radio amateur |publisher=[[American Radio Relay League]] |date=1977 |pages=82–87}}</ref>
<ref name="Lundstrom_2006">{{cite book |author-last=Lundstrom |author-first=Lars-Ingemar |title=Understanding Digital Television: An Introduction to DVB Systems with Satellite, Cable, Broadband and Terrestrial |publisher=[[Taylor & Francis]] |date=2006 |location=USA |pages=81–83 |url=https://books.google.com/books?id=IW-iqhtqYGMC&q=%22satellite+receiver%22+LNB+%22intermediate+frequency%22&pg=PA81 |isbn=0-24080906-8}}</ref>

<ref name="Redford_1996">{{cite web |author-last=Redford |author-first=John |title=Edwin Howard Armstrong |date=February 1996 |work=Doomed Engineers |publisher=John Redford's personal website |url=http://world.std.com/~jlr/doom/armstrng.htm |access-date=2008-05-10 |url-status=dead |archive-url=https://web.archive.org/web/20080509070320/http://world.std.com/~jlr/doom/armstrng.htm |archive-date=2008-05-09}}</ref>

<ref name="Wiccanpiper_2004">{{cite web |author=Wiccanpiper<!-- alisdair --> |title=Superheterodyne |date=2004-01-08 |work=everything.com |url=http://everything2.com/index.pl?node_id=1356743 |access-date=2008-05-10 |url-status=live |archive-url=https://web.archive.org/web/20210709224144/https://everything2.com/index.pl?node_id=1356743 |archive-date=2021-07-09}}</ref>

<ref name="Ravalico_1992">{{cite book |author-last=Ravalico |author-first=Domenico E. |title=Radioelementi |language=it |location=Milan, Italy |publisher=Hoepli |date=1992}}</ref>

<ref name="Bussey_1990">{{cite book |author-last=Bussey |author-first=Gorden |date=1990 |title=Wireless: the crucial decade - History of the British wireless industry 1924–34 |publisher=Peter Peregrinus Ltd. / [[Institution of Electrical Engineers]] |publication-place=London, UK |volume=13 |series=IEE History of Technology Series |isbn=0-86341-188-6 |id={{ISBN|978-0-86341-188-5}} |pages=18–19, 78 |url=https://books.google.com/books?id=QJzDsSuaqU4C&pg=PA78 |access-date=2021-07-11 |url-status=live |archive-url=https://web.archive.org/web/20210711072729/https://books.google.de/books?id=QJzDsSuaqU4C&pg=PA78&lpg=PA78&ots=D8X5i8YOP-&focus=viewport&vq=30+kc%2Fs&dq=Wireless+-+the+crucial+decade+1924%25E2%2580%25931934&hl=de |archive-date=2021-07-11}} (136 pages)</ref>
}}

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[[Category:Radio electronics]]
[[Category:Broadcast engineering]]