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Small Deep Space Transponder Small Deep Space Transponder
X-Band and Ka-Band
C4 Systems
Features
Deep-Space Network Compatible
Redundant I/O for Cross-Strapping
X-Band Receiver, X-Band and Ka-Band Exciters
2.0 dB Noise Figure (Nominal 25° C)
-157.7 dBm Receiver Threshold (Nominal 25° C)
Temperature Compensated Receiver VCO
Low Exciter Spurious, Phase Noise and
Allan Deviation
Radio Science Mode (using USO Input)
10 ns Typical Ranging Delay Variation
8 Mbps Maximum Telemetry Symbol Rate
0.5 ns Typical Carrier Delay Variation
MIL-STD-1553 Interface - Standard and Low Power
External Power Converter Synchronization Capability
Operates Under Launch Environments
Radiation and SEU Resistant
Internal Telemetry Modulation Encoder
Internal Command Detector
Mounting in Either of Two Axes
Firmware Options:
-Carrier tracking loop bandwidth
-Command detector subcarrier frequencies and
data rates
-Custom Command/Telemetry Interface format
ASIC, the SDST's flexible design provides the
capability to meet the telecommunication needs of
nearly every deep-space mission in a package which
offers significant reductions in size, weight, power and
cost over previous designs.
The Small Deep Space Transponder (SDST), developed
by General Dynamics and NASA's Jet Propulsion
Laboratory, provides the spacecraft terminal for
X-Band and Ka-Band telecommunications with the
NASA Deep Space Network. Making extensive use of
MMICs, multi-chip modules and a signal-processing Small Deep Space Transponder
8201 E. McDowell Road, MD H2099, P.O. Box 1417 Scottsdale, AZ 85252-1417 Tel 1-800-626-6626 www.gdc4s.com/space
© 2004 General Dynamics. All rights reserved. Specifications subject to change without notice.
C4 Systems
Transponder
X-Band Uplink Frequency Range (Fixed Channel): 7.145 - 7.235 GHz
X-Band Downlink Frequency Range (Fixed Channel): 8.400 - 8.500 GHz
X-Band Tx/Rx Ratio: 880/749
Ka-Band Downlink Frequency Range (Fixed Channel): 31.800 - 32.300 GHz
Ka-Band Tx/X-Band Rx Ratio: 3360/749
Carrier Delay Variation: < 3 ns p-p
Ranging Delay Variation: < 40 ns p-p
X-Band Receiver
Exciters
(Independent X & Ka-Band)
General
Noise Figure: < 2.5 dB @ 25° C
Carrier Tracking Signal Range: -70 to -156 dBm
Carrier Loop BW (2-sided): 20 Hz nom. at threshold (expands to 200 Hz,
strong signal)
Carrier Loop Damping Factor: 0.5 @ 0 dB loop S/N (Type 1, 2nd
order loop)
Tracking Range: > ±200 kHz
Command Subcarrier Frequency: 16 kHz
Command Subcarrier/tone Mod Index: 0.2 - 1.5 Rad. pk
Command Data Rates: 7.8125 - 2000 bps (2n steps, PM/PSK, NRZ)
Ranging Uplink Mod Index: 0.8 - 1.2 Rad. pk
Ranging Filter type: 3-pole Chebyshev (other options available)
Ranging Filter BW (3 dB): 1700 kHz nom. (other options available)
Temperature Stability: ±3ppm (-20° C to +60° C)
X-Band Output Power: +13 dBm @ 25° C nominal
X-Band Residual Phase Noise: -20 dBc/Hz (1 Hz offset)
-75 dBc/Hz (100 Hz - 100kHz)
Ka-Band Output Power: +4.0 dBm @ 25° C nominal
Frequency Stability, 0°C to 50°C: 5.0 ppm maximum
Spurious & Harmonic Outputs: < -50 dBc
Phase Modulator Linearity: < 10% to 2.0 rads pk
TLM Format: NRZ-L
TLM Convolutional Encoding: 15-1/2, 15-1/4, 15-1/6, 7-1/2,
TLM Subcarrier: Programmable 2 kHz to 4 MHz sq. wave (1 Hz steps)
TLM Phase Deviation: 0° to 90° peak (2° steps)
Ranging Modulation Index: Selectable (4.375, 8.75, 17.5, 35, 70° pk.)
Differential One-way Ranging Tones: 19.2 MHz, coherent w/downlink carrier
Direct Modulation Mode: Available (rates to 8 Mbps)
BI-ø-L Coding: Available
Mass: 2.9 kg maximum
Power:
Receiver Only: +11.9 W nominal
Add X-Band Exciter: +2.2 W nominal
Add Ka-Band Exciter: +3.8 W
Volume: < 2681 cc (11.3 cm H x 17.4 cm W x 13.4 cm D)
Input Voltage: +22 to +36 VDC
External Synch Frequency: 125 kHz nominal
Radiation Total Dose: 50 krads (Si) (part level), 100 krad option
Operating Temperature: -40° C to +60° C)
D-SDST-1-0205
Performance Characteristics