Hello all,

well, after a long delay, I've been able to dedicate a little time to my
idle project: a home built spectrum analyzer based on a TV tuner front
end.

I've found what I believe the perfect tuner for me (mostly because it's
something I have in my hands):

http://www.datasheetarchive.com/indexdl/Datasheet-028/DSA00488547.pdf

It's a Temic 4036 RF front end module. I found it on a WinTV PC TV tuner
PCI card.=20

It's a I2C based tuner, with single 5V power supply (has an onboard
DC-DC to get the 33V needed by the tuner). I stuck the card in a PC,
booted Ubuntu, attached a protocol analyzer (thank you beta version of
the BitScope software, was a major time saver!) on the I2C pins, started
TVTime and changed channels. The module is being programmed exactly as
the datasheet says it should be!

So, with that out of the way, what would be my next step?

First off, the module outputs CVBS (at baseband), and something labelled
IF2 (at 45.75 MHZ). Obviously I need an RSSI circuit. But do I first
have to "tune" the output somehow?=20

What I'm envisioning (and note, I no NOTHING about RF stuff, so this is
very much a learning project for me) is using a second tuner (some sort
of home built one chip thing with RSSI output perhaps?) that "tunes"
somewhere in the CVBS output with a bandwidth of say 10kHz? So basically
sweeping would be two steps, set the TV tuner to a channel, then sweep
the second tuner across the ~4MHz bandwidth of the CVBS or IF output.
Then step the TV tuner to the next range, and sweep the CVBS or IF
output. Combined I could get everything I need.

Does this sound at all reasonable or am I WAY out of wack here?

Should use the CVBS or the IF output?

Anybody have chip recommendations for how I might build the second
tuner, one hopefully with an RSSI output?

Is there a simpler way to what I'm after? What kind of resolution should
I aim for?

Thanks for any pointers!

TTYL

--=20
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