The FSK002 is a high performance FSK/AM/PM Modulator which produces SGLS (Space Ground Link Subsystem) compatible sub-carriers. Selectable modulations include: FSK, FSK/AM, FSK/PM, FSK/AM/PM. The module accepts SGLS dibit encoded serial data and clock, or ternary (1,0,S) data and clock inputs for Ternary FSK modulation. External serial data (AUX) or the internal PRN data generator are selectable sources used for binary FSK modulation. The FSK output level is adjustable from -30 to +20 dBm (into 75 Ohms). A fixed-level FSK Test Point output is also provided. The PRN data and coherent clock are also provided as outputs.

A digital frequency synthesizer is utilized to produce SGLS tri-tone signal frequencies. Each FSK tone is tunable to 5MHz. (All FSK001 signals are generated by Direct Digital Synthesis (DDS) and are accurate to 100 ppm (1 ppm optional).) Any combination of the ternary frequencies are selectable for the binary FSK tone pair. The FSK signals can be amplitude modulated with a triangular wave, supporting fixed command symbol rates of 1 Ksps, 2 Ksps, 5 Ksps or 10 Ksps. If AM is turned OFF, the FSK modulation data rate is tunable to 100 Kbps. The resultant FSK or FSK/AM signal can either be output or used to Phase Modulate a sub-carrier.

All user selectable parameters are controlled via the ISA bus interface.

The FSK002 provides support for testing and up-link commanding in the SGLS environment. The internal PRN data generator is a data source that may be used to perform bit error testing on the data link.