The PMM005 is a multifunction module comprising a set of four clock & data digital interfaces, a four-input signal summer, a linear phase modulator, and an upconverter.

Four level-converters are provided for input clock & data signals that convert RS422 to TTL levels. Typically, these are used to drive BPSK modulators. In addition, any departure in the input clock waveform, from the ideal 50% duty cycle, is corrected. Four (4) subcarrier modulator outputs are applied to a linear signal Summer contained on the PMM005 module. The individual signal amplitudes are controlled on the modulators to create a composite signal with appropriate component power levels. On the PMM005, the composite signal level is adjusted prior to its application to a Phase Modulator.

The composite signal output from the Summer is used to phase modulate a 12 MHz subcarrier. This phase modulated 12 MHz subcarrier is upconverted to 70 MHz by heterodyning with a 58 MHz local oscillator. The output level of the 70 MHz IF PM carrier is programmable over a 20 dB range. A sample of the 70 MHz output is provided as a monitor output for connection to a test point. The output of the Summer and the 12 MHz subcarrier output of the Phase Modulator are also connected to monitor connectors.