1-70
HIGH-LEVEL MODULATION is modulation produced in the plate circuit of the last radio stage
of the system.
LOW-LEVEL MODULATION is modulation produced in an earlier stage than the final power
amplifier.
The PLATE MODULATOR is a high-level modulator. The modulator tube must be capable of
varying the plate-supply voltage of the final power amplifier. It must vary the plate voltage so that the
plate current pulses will vary between 0 and nearly twice their unmodulated value to achieve 100-percent
modulation.
