Re: Has anyone here have an AM transmitter and what is best one to buy?
Posted: Mon Oct 03, 2016 12:25 am
Mike - that's exactly the trick.
These days it's done with a chain of op-amps with all-pass filters, but when Kahn came up with "his" system in the 50s, it used lots of LC filters in a large, heavy box. The inductors were huge - like big transformers - and it used silvered mica capacitors for accuracy. It was a sealed box, and covered by all sorts of Patents and legal indemnities against the circuit being disclosed.
Some station engineers complained that the Kahn processor had "blown up" their transmitters by working the modulator "too hard" - in reality, these were under-powered, under-specified cheap transmitters, and would probably have failed anyway!
The effect of Kahn's magic box is to even out the modulation and allow the modulation depth to be close to maximum all the time, giving a LOUD-sounding signal. This processor, in combination with an LA2 compressor and a negative peak clipper was the "industrial standard" in the 'States from to 50s to the early 80s.
These days it's done with a chain of op-amps with all-pass filters, but when Kahn came up with "his" system in the 50s, it used lots of LC filters in a large, heavy box. The inductors were huge - like big transformers - and it used silvered mica capacitors for accuracy. It was a sealed box, and covered by all sorts of Patents and legal indemnities against the circuit being disclosed.
Some station engineers complained that the Kahn processor had "blown up" their transmitters by working the modulator "too hard" - in reality, these were under-powered, under-specified cheap transmitters, and would probably have failed anyway!
The effect of Kahn's magic box is to even out the modulation and allow the modulation depth to be close to maximum all the time, giving a LOUD-sounding signal. This processor, in combination with an LA2 compressor and a negative peak clipper was the "industrial standard" in the 'States from to 50s to the early 80s.