System Architecture Overview
Spectrum replicator and coherent de-spreader design engineered for Ultra Small Aperture Terminals (USATs).
Technology Overview
Designed for SCPC and TDMA multiple-access return channels, offering spectrum spreading to control adjacent satellite interference alongside coherent gain recovery at the de-spreader.
Spreader Characteristics
- Reduces transmit signal power spectral density (PSD), significantly diminishing interference from USAT remotes to adjacent satellites.
- Functions as a spectrum replicator, incorporating carrier phase shifts specifically designed to minimize Peak-to-Average Power Ratio (PAPR).
De-Spreader Characteristics
- Innovative architecture eliminates the necessity for dedicated frequency acquisition.
- Applies a least squares fit of estimated phases to minimize variance under low SNR operating conditions.
- Coherent combining of sub-carrier signals delivers up to 5.5 dB processing gain in SNR.
Measured Link Performance
Experimental measurements of DVB-RCS2, BPSK-1/2, 512 ksps return link utilizing a 4x spreader and de-spreader configuration:
| Es/N0 at De-Spreader Input (dB) | Es/N0 at De-Spreader Output (dB) | De-Spreader Gain (dB) |
|---|---|---|
| 9.7 | 13.7 | 4.0 |
| 5.1 | 10.3 | 5.2 |
| 0.0 | 5.6 | 5.6 |
| -5.0 | 0.6 | 5.6 |
| -6.0 | -0.5 | 5.5 |