AMPLITUDE MODULATOR HAVING A TRANSISTOR CONTROLLED BIAS CURRENT

摘要

An amplitude modulator capable of 100% modulation with low modulation distortion, adaptable to all practical amplitude modulation requirements from D.C. to 120 MHz. The circuit has a differential amplifier with an R.F. input and a bias current from an ultra-linear, voltage-tuned constant current source which is transistor controlled. The differential amplifier provides full limiting of the R.F. input and is biased with a current source comprised of an operational amplifier with its feedback connected to include the bias current controlling transistor.