RadioBanter - quadrature detector & SSB

On Fri, 7 Jul 2006 17:28:54 -0500, "Steve N."
wrote:

"MAc" wrote in message
...
Steve N. napisa³(a):

AD607 does NOT have a "quadrature detector". It has an "I & Q
demodulator".
BIG difference. You must read the datasheet and app notes to use it
correctly. It is capable of demudulating many types of modulation.
[typo
accepted]

My mistake, I undersand. But datasheet says nothing more exept "it is
possible to detect ssb with ad607"

Thanks
MAc

OK MAc,
All I know is the I & Q modulator and demodulators are the industry
standard in commercial radios like the ones my company designs. I hrae that
you can get anything you want. I'm too far away from the current designs to
know anything specific.
A Google resulted in this , but it doesn't appear to be a complete how-to.
http://www.merrimacind.com/rfmw/02intro_modulators.pdf

Perhaps someone can explain how to "I & Q" to get SSB, etc.

Good luck 73, K9DCI

Havent looked much at the AD part but... it's a mixer
(actually two of them).

See articles by KK7B and Breed. Basically the I (inphase)
and Q (quadrature) mixers are fed with RF at 90 degree relation to
each other. The resulting output is then put through a 90degree
delay (use 3rd order allpass networks for that) and sum or difference
the result and you have a phasing SSB/CW reciever. If you can keep
the phase and amplitude errors better than 1% (easy with modern parts)
you get 40+ db of alternate sideband suppression. All the work is
done in the audio range so Opamps are good for this or DSP. Look up
R2, MIniR2, or R2pro for more details. Summary is if you delay the
Q path by 90degrees and add the result there will be a frequency(s)
where the results add to each other and as you get past zero beat they
will subtract from each other.

One note on alternate sideband suppression, 40db is pretty good
sounding, 50db is achieveable and 60db is tough.

I've built a SSB transceiver using the KK7B miniR2 design and opposite
sideband suppression is 45db or so and it sounds far better on the air
than the typical minimal RX with a 4 crystal ladder filter. I run a
MiniR2 and T2 (phasing TX) on 6m with a 6W output. Gets rave reviews
for clean signal and it's very good TRX for DX.

Allison