11-11-2015, 06:03 AM
Going on the schematic I posted earlier, for the sake of it I'll call the left hand diode D1 and the right hand diode D2:
This is my take on it but see what the rest of the gang make of it, it looks like simple AGC to me as at the moment I can't see anything that introduces a delay voltage.
D2 ls the detector diode which the AGC line is derived from.
Also note that there is no cathode bias used on the mixer or the IF amp, because of that I think the contact potential of D1 is used instead, hence the high value resistor (5.6 megohm) that connects the AGC voltage from D2 to the AGC line.
Below is a link to what is basically another version of the schematic, it uses the same AGC arrangement, some voltages are given including the AGC line voltage, the voltages might have been measured under no signal conditions:
http://a402.idata.over-blog.com/3/44/57/...E-1956.jpg
Lawrence.
This is my take on it but see what the rest of the gang make of it, it looks like simple AGC to me as at the moment I can't see anything that introduces a delay voltage.
D2 ls the detector diode which the AGC line is derived from.
Also note that there is no cathode bias used on the mixer or the IF amp, because of that I think the contact potential of D1 is used instead, hence the high value resistor (5.6 megohm) that connects the AGC voltage from D2 to the AGC line.
Below is a link to what is basically another version of the schematic, it uses the same AGC arrangement, some voltages are given including the AGC line voltage, the voltages might have been measured under no signal conditions:
http://a402.idata.over-blog.com/3/44/57/...E-1956.jpg
Lawrence.
