Talk:Intermediate-frequency amplifier

There is no talk page, so now I create one. Gah4 (talk) 03:32, 25 January 2019 (UTC)

Discussion

There is discussion on merging this with Intermediate frequency. I believe that it is worth having this article, but the current one says little enough, that for now I would suggest a redirect. This article could mention the bandwidth, tuning (IF tranformers), flat frequency response over the IF bandwidth, and such. It might mention tuned RF receivers and the problems that they have, that led to the use of IF, and the rapid changeover to such receivers. Tuned RF requires tuning capacitors for each amplifier stage, complicating design, alignment, and use. (TRF receivers have three or more tuning dials on the front, that all have to be adjusted for each station.). Gah4 (talk) 03:32, 25 January 2019 (UTC)

• Support - for above reasons. --Chetvorno^TALK 05:45, 25 January 2019 (UTC)

Well, I was suggesting keeping this article, but much expanded. (Not that I volunteer to expand it.) If you merge, what would you move into the other one? Gah4 (talk) 08:14, 25 January 2019 (UTC)

@Gah4: Sorry, I guess I misunderstood. What was your proposal? "...for now I would suggest a redirect." Redirect what to what article? --Chetvorno^TALK 00:38, 29 January 2019 (UTC)

Well, it used to say almost nothing, so not much to merge, other than the references. One might copy the references over. I made some changes, which I believe are a start to an actual useful article. The Intermediate frequency article should be mostly about the theoretical ideas, where this one would be more practical. WP:NOTHOWTO, but some about how IF amplifiers actually work, IF transformers, tuning, and what seems to be called alignment. I now have an RF signal generator, and if I get in the right mood, will try to align some receivers. This will soon be a lost art, so some things could reasonably go here. I also have a TRF radio (from 1927) that I might try to get working some day. Thanks. Gah4 (talk) 03:22, 29 January 2019 (UTC)

Yeah, eventually there should be enough to make a good sized article. Historical IF transformers and alignment, AGC, modern crystal lattice filters, integrated circuit versions, what qualities make a good IF amplifier, selectivity, FM stereo reception, comparison to digital IF signal processing. The current contents justifies merging it into Intermediate frequency, but we would eventually just have to separate it out again. --Chetvorno^TALK 00:24, 30 January 2019 (UTC)

Most of what is there now, I wrote in the last few days. I think it is on the way to being a good and useful article. Gah4 (talk) 02:50, 30 January 2019 (UTC)

IF transformers and alignment

There is Transformer_types#IF_transformer which says much less than most of the rest of the Transformer types article, but could be linked one or both ways. Also, how arrangements of tuned IF transformers make an IF amplifier with sufficiently flat frequency response over the desired frequency range, such as the about 6MHz bandwidth for analog TV signals. (Not that I know how to do this, but I have read about it and read TV schematics.) Such discussion probably doesn't go into Intermediate frequency, so could go here. Also, I believe that AGC is mostly implemented in the IF amplifier, so that could be discussed, too. There is, for example: how to align receivers, though being considerate of WP:NOTHOWTO. Otherwise, I don't see much here now to actually merge. Gah4 (talk) 08:32, 25 January 2019 (UTC)

For wideband fixed tuning circuits (as used in IF amps) see double-tuned amplifier and staggered tuning. SpinningSpark 12:14, 29 January 2019 (UTC)

Yes. I like the way they use the same figure with different explanations in the two articles. I believe that details like that should go here, and not into Intermediate frequency, though. Even more, how to make the IF amplifier response for vestigial sideband reception. Gah4 (talk) 18:05, 29 January 2019 (UTC)

converters

Should frequency converters be discussed here? There used to be boxes that would convert UHF TV signals to VHF, for older TV sets, where the output is the IF of the conversion. Also, older cable TV set-top boxes worked this way. There are also CB to AM broadcast band converters that work this way. Some converter boxes upconvert, and then back down again. Gah4 (talk) 05:58, 4 February 2019 (UTC)

No, those are off-topic. Dicklyon (talk) 06:50, 4 February 2019 (UTC)