A direct synthesis transmitter. A very efficient and highly linear direct
synthesis transmitter is provided that can be used to directly synthesize
and transmit any type of modulated signal. The direct synthesis
transmitter includes a phase-locked loop (PLL) with controls phase
modulation plus an accompanying variable gain amplifier for amplitude
modulation. Also included is a system to align the phase and amplitude
modulation signals. A transmitter constructed in accordance with the
present invention is very efficient and suitable for use in portable
radio equipment.