dougm@pnet51.orb.mn.org (Doug Mcintyre) (03/26/91)
I've been studying up on TV tuner circuits for various projects I'd
like to do around here. I haven't gotten into any chips that exist though for
help with this stuff. All I've seen is National's old linear data book. I was
looking for something like a chip that took the standard IF out of the
mechanical tuner, and fed back its AGC and AFT signals and put out baseband
video and audio. Anything like this? It is part of a chip in my acient
panasonic VCR, but there should be just a single part that does this? (I doubt
I could find a source for the panasonic custom chip).
Are there other chips for use in digital tuners?
Any data books recomended for their standard video chips (ie. Motorola?)
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INET: dougm@pnet51.orb.mn.org GENIE: D.MCINTYRE1asd@cbnewsj.att.com (Adam S. Denton) (03/26/91)
In article <4405@orbit.cts.com> dougm@pnet51.orb.mn.org (Doug Mcintyre) writes: > >help with this stuff. All I've seen is National's old linear data book. I was >looking for something like a chip that took the standard IF out of the >mechanical tuner, and fed back its AGC and AFT signals and put out baseband >video and audio. Anything like this? It is part of a chip in my acient My choice in this regard is the TDA2540 or TDA2541, available from ECG and NTE as ECG 1413 or ECG 1545. Yes, it's expensive from them (NTE1413=$5) but nobody on the planet other than MCM electronics sells the little bugger in hobbyist quantities. It's a 16-pinner with 2-coil design with AFT and AGC with 12V supply. National used to have it (in their big fat '82 linear book). They still may. Look it up there for an applications circuit (signetics also makes it too). It doesn't have audio, though. I just stick on a MC1358/CA3065/ECG712 demod chip if I need sound. These are sold everywhere. The versions vary as to the polarity of the RF AGC output. I figure it's easy enough to level-translate that output with a single xistor if I need to that I just get whatever version is cheapest. Some of the chips in the Digi-Key catalog may be what you want, if you must have a one-chip solution -- check the Samsung chips. Look 'em up in the ECG catalog to see if they look like what you'd want. Getting data on 'em might be difficult though. Motorola is working on a ONE-coil design chip...!!! Also, old TVs are good sources for other things you might need -- like a 4.5MHz ceramic filter and/or SAW (if you find a SAW you're very lucky!)... Bear in mind that in the absence of a SAW, you'll need to play games with "traps" for 47.25 and possibly 39.25 MHz or you'll have adjacent-channel interference. Even with a SAW, typically you'll still need the 47.25. Adam Denton asd@mtqua.att.com
rick@ameristar (Rick Spanbauer) (03/27/91)
In article <4405@orbit.cts.com> dougm@pnet51.orb.mn.org (Doug Mcintyre) writes: > I've been studying up on TV tuner circuits for various projects I'd >like to do around here. I haven't gotten into any chips that exist though for >help with this stuff. All I've seen is National's old linear data book. I was >looking for something like a chip that took the standard IF out of the >mechanical tuner, and fed back its AGC and AFT signals and put out baseband >video and audio. Anything like this? It is part of a chip in my acient >panasonic VCR, but there should be just a single part that does this? (I doubt >I could find a source for the panasonic custom chip). >Are there other chips for use in digital tuners? > >Any data books recomended for their standard video chips (ie. Motorola?) I went through this hassle of trying to get info from eg Motorola on their consumer electronic semiconductors. Since the domestic consumer electronic industry is all but dead, it is hard to get information on CE silicon from the usual sales offices. People either don't know the chips exist, or they will not sell them in small quantities. In particular, if all you are interested in is to build a TV tuner, then I would recommend you get a hold of one of the Asian electronics importer catalogs and buy a tuner from them. They are surprisingly cheap ($10-$15 US), people will sell in small quantities, and accept payment via wire transfer. Alternatively, you could buy a tuner from eg the Sony, RCA, or Panasonic repair centers, though these will cost substantially more. Modern tuners are available with all the PLL control circuitry already embedded - just supply +33V for the varactors, +12V, +5V, serial clock/data, and you get IF or baseband out. Rick Spanbauer Ameristar
markz@ssc.UUCP (Mark Zenier) (03/29/91)
In article <4405@orbit.cts.com>, dougm@pnet51.orb.mn.org (Doug Mcintyre) writes: > >I was > looking for something like a chip that took the standard IF out of the > mechanical tuner, and fed back its AGC and AFT signals and put out baseband > video and audio. Anything like this? The Signetics TDA2540, TDA2541, TDA2549 Video IF amplifier/demodulators. > > Any data books recomended for their standard video chips (ie. Motorola?) Find a MegaCorp that makes TV sets and semiconductors. Phillips/Signetics, SGS-Thomson, Samsung, Sanyo, Hitachi, ... Mark Zenier markz@ssc.uucp mzenier@{polari ? seattle}.uucp