When we read in QST about Bill Carver RX IF AGC we were impressed about the design and we wanted to try to duplicate that design. Here is our completed board:
The small rectangular enclosure is an home built 3 quarz 9 Mhz IF filter which is an interstage bandpass filtering, but the main selectivity is in another board at the input of this IF AGC amplifier. This unit is capable of about 120 dB range of input signal with a constant output, so pay attention to the fact that this board is capable of  very high gain concentrated in one board and so a very high selectivity is needed in front of this board along with low noise preceding stages, well filtered power supply and well shielded enclosure. We tried to duplicate this unit some months after Bill Carver (K6OLG, now W7AAZ) article appeared  in QST magasine in 1996: "A High Performance AGC/IF Subsystem", QST May 1996 p.39-44(.pdf file is in the 2003 ARRL book+CD below) and errata corrige in Dec 1996 QST, p. 71.

See the implementation of W7AAZ design in the CDG2000 project at their website (click this blu link)
We like also an RX Mosfet IF agc ampl. similar to the one presentend in the new ARRL book "Experimental Methods in RF Design" by W7ZOI,KK7B,W7PUA, ed. Feb. 2003, pag 6.24, chapter 6, and multi point distributed gain/agc. Some years ago we used a similar one from VHF Communication magazine in our 1993 home built TRX
Digital Automatic Gain Control for Radio Transceivers by KF6DX Doug Smith (QEX Editor) A link to an on line article for a  digital approach in modern transceivers about  agc/alc control.


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