Description
The Model 784 SGLS Signal Generator is a high performance FSK/AM/PM Modulator which produces Space Ground Link System (SGLS) compatible command sub-carriers. A tri-tone Frequency Shift Keyed subcarrier is either output directly or Amplitude Modulated. The resultant FSK or FSK/AM signal may be used to Phase Modulate a second subcarrier. The sub-carrier output power level is adjustable from -30 dBm to +20 dBm, or can be turned off. An adjustable rate clock source drives a selectable tap PRN data generator which is available to be used as a modulation source. Both the clock and PRN data are output to the rear panel. Direct Digital Synthesis is used to generate FSK and PM subcarriers, and the PRN clock.
The Model 784 performs binary (two tone) and ternary (three tone) FSK modulation using either internally generated data or an external data source. The FSK frequencies are selectable as a set of 65 kHz (S), 76 kHz (0), and 95 kHz (1); 355 kHz (S), 366 kHz (0), and 385 kHz (1); or 975 kHz (S), 1024 kHz (0), and 1073 kHz (1). Other frequencies sets can be provided. Ternary FSK requires external data and clock as the modulation source. The format of the data is either frame formatted dibit encoded serial data, or ternary (three signals- S, 0, and 1). For binary FSK, either the internal PRN data generator or the external auxiliary (SERIAL) data and clock input can be used. In binary FSK mode, any two of the three FSK tones can be selected. Internal PRN data rates of 1 kbps, 2 kbps, 5 kbps and 10 kbps are selectable (other rates to 100 kbps are optional).
Features
• Accepts Tertiary or Dibit Encoded Data
• Generates Selectable SGLS Tri-Tone Signals
• SGLS Command Rates – 1kbps, 2kbps, 5kbps, 10kbps
• Low Phase Noise Digital Frequency Synthesizer
• Selectable Modulations – FSK, FSK/PM, FSK/AM and FSK/AM/PM
• Internal PRN Data Generator – Selectable Taps
• Remote Control – ASCII Commands and RS-232, IEEE-488
