Talk:Intermediate frequency

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From an email to Wikimedia:

"While no factual errors, the omission of the most common IF (Intermediate Frequency) for FM radios, 10.7 MHz, used since the 1940s when FM first came about is glaring. Virtually any FM broadcast radio you pick up today will have a 10.7 MHz IF in it. Many will also often have a second IF at 455 kHz.

True, the listed 455 kHz is also the most common IF in AM and single conversion radios, but the other two IFs listed are brand-specific random choices of frequencies. 10.7 MHz has been a staple of nearly every brand of modern FM radio ever produced, tube or certainly solid state, since FM's inception in the 1930s. So much so, NOT using 10.7 MHz specifically identifies some brands (e.g., 10.8 MHz was 'unique' by patent to Electra Bearcat scanner radios)."

Can someone review and make any edits neeed? This isn't my area. Thanks -- sannse (talk) 20:38, 21 January 2006 (UTC)

The 10.7 MHz IF for FM is used for a number of countries, but not all. There are two or three other commonly used IF Frequencies throughout the world for FM. The situation is similar for AM IF frequencies, but I think there are more different ones used. -- (talk) 18:13, 12 November 2012 (UTC)

Other common intermediate frequencies ...[edit]

`Other common intermediate frequencies are 2400MHz (WLAN), 2000MHz (Cellular/WLAN), 850/900/1800/1900MHz (Cellular)'

Um, wouldn't these be the actual frequencies used by these applications, rather than intermediate frequencies? dougmc 22:40, 16 June 2006 (UTC)

Please note that these are the actual RF frequencies and not the IF frequencies. Make correction kindly.

Clean up 1/9/07[edit]

Cleaned it up a little bit since the sentences were repetitious. --SamMichaels 15:31, 9 January 2007 (UTC)

Revision 159334848 by [edit]

You changed the IMF of television from 30mhz to 41mhz. How can you explain this when common TV modules which use varying frequencies in 30mhz:

  1. 36.00
  2. 36.13
  3. 36.16
  4. 36.167
  5. 38.9

--SamMichaels 13:50, 21 September 2007 (UTC)

System B[edit]

I added the intermediate frequencies of the international system B (G.H etc.) Nedim Ardoğa (talk) 18:17, 28 October 2009 (UTC)

Zero Intermediate Frequency[edit]

I would like to see a link to the article on "Zero Intermediate Frequency". Also, it would be good to see an explanation of why IFs different from zero are used. If I had to design one of these systems, f=0 comes to mind as the first candidate for an IF. So the question is: why is IF=0 not used? —Preceding unsigned comment added by Avalcarce (talkcontribs) 08:28, 2 March 2010 (UTC)

You get issues with DC offset, see Homodyne receiver for that topic --Moritz der Moralapostel (talk) 12:51, 28 September 2010 (UTC)
In addition, it is harder to build amplifiers with flat frequency response. At IF, the bandwidth is small compared with the center frequency, making a flat response easier. The design of a receiver involves choosing how much amplification to do at RF (input frequency), IF (one or more), and at baseband (what you call f=0). Note for an audio (stereo) amplifier, it is generally specified as 20Hz to 20kHz, a ratio of 1000. For an FM receiver with a 10.7MHz IF, and with the 200kHz bandwidth, the amplifier needs to be fairly flat form 10.6MHz to 10.8MHz, much easier to build. Gah4 (talk) 21:34, 28 March 2017 (UTC)