Datum Systems PSM-4900 70Mhz IF Band satellite modem

Description

Datum Systems PSM 4900 70MHz satellite modem serial number 5200.  Additional modem serial # 10032, 10033, 4184, 7702, 7676, 3758, 9015, 4296 (not pictured in listing)
IF OUTPUT
Output Frequency Range :   IF  50.000 to 90.000 MHz.
Tuning Method:  Via internal synthesizer.
Output Level Control: Programmable in 0.1 dB steps over 40 dB from +5 to -35 dBm, +3 dBm max at 50Ω standard unit
Output Level Accuracy/Stability:  ± 0.5 dB over 0 - 50°C @ any level or frequency ± 0.25 dB over any 10°C range.
Output Impedance:  Programmable 50 or 75Ω.
Output Return Loss:  20 dB minimum
Output Burst Control:  Contact factory for burst definition and capability.
Output Burst Off Isolation >60 dB
Modulation
Technique: BPSK or QPSK Selectable.
Spectral Density: The modulated band shall be -3 dB at the Nyquist frequency of the symbol rate, then approximating an n=8 Butterworth filter response.
Spurious Output:  < -50 dBc from 2 to 200 MHz.
Harmonic Output:  < -50 dBc.
Phase Balance: < 1 degree.
Transmit Synthesizer
Tuning Step Size: 1 Hz steps.
Frequency Stability: ± 2.0 ppm. (176 Hz max) internal reference
Aging:  ±1 ppm per year using internal reference.
Phase Noise:  <-87dBc @1kHz. <-93dBc @10kHz. <-108dBc @100kHz.
Synthesizer Control: Via Front Panel and serial control port.
Transition Time:  < 100 msec. to any frequency including command latency.
Transmit Baseband Processing
Data Rate: Variable under program control. Rates hold for Viterbi or Turbo Product Codes FEC. FEC Rate 1/2.
Any data rate from 1.2 kbps to 1,230 kbps BPSK. Any data rate from 2.4 kbps to 2,460 kbps QPSK. FEC Rate 3/4 or 7/8 Any data rate from 2.4 kbps to 2,460 kbps BPSK. Any data rate from 4.8 kbps to 4,920 kbps QPSK. Note: Maximum rates are limited using Reed-Solomon and IBS Multiplexer Options
Settability  Any rate settable to 1 bps increments. Accurate to 2 PPT at rate 1/2, or 4 PPT, rate 3/4 or 7/8, relative to either internal (nominally 2.0 ppm) or external reference clock as selected.
Data Clock Tracking Range External or Terminal Timing = +/-400 ppm. Reverts to internal clock outside this range.
Data Rate Clock Sources  a. Internal. b. Terminal Timing input on data connector c. External input on data connector.
d. Receive Clock recovered from demodulator.
Forward Error Correction: Convolutional encoder, k= 7. Rate 1/2. G0 code = 171 octal, G1 code = 133 octal. Rate 3/4 or 7/8 using punctured code Optional Reed-Solomon Concatenated Codec and Turbo Product Codes Available
Differential Encoding: Selectable On or Off @ Front Panel and via serial control port.
Scrambler: IESS-308 or 309, Intelsat and V.35 selectable with enable @ Front Panel and via serial control port. IBS and Reed-Solomon specific modes are available when these options are installed.
Demodulator Specifications
IF Input Input Frequency Range  : 50.000 to 90.000 MHz
Tuning Method:  Via internal synthesizer.
Input Carrier Level:  -20 to -84 dBm total. 40dB range window shifts with the data rate. Lower levels at lower rates.
Acquisition/Tracking Range:  ± 100 Hz and ± 1.25 MHz in 1 Hz increments.
Smart reacquisition:  In “Search” mode the demodulator will search for return of a lost carrier within a specified range for a selected time before reverting to full acquisition range. Reacquisition range: ± 100 Hz and ± 1.25 MHz in 1 Hz increments Reacquisition sweep time: 0.1 to 6000 seconds in 0.1 second increments.
Input Impedance: Programmable 50Ω or 75Ω.
Input Return Loss:  20 dB
Modulation Technique:Selectable BPSK or QPSK.
Type of demodulation: Continuous Coherent.
Receive Synthesizer
Tuning Step Size: 1 Hz steps.
Frequency Stability:  ± 2.0 ppm. (176 Hz max) internal reference
Synthesizer Control: Front Panel and via the Serial Control port.
Receive Baseband Processing
Data Rate: Variable under program control. Rates hold for Viterbi or Turbo Product Codes FEC. FEC Rate 1/2. Any data rate from 1.2 kbps to 1,230 kbps BPSK. Any data rate from 2.4 kbps to 2,460 kbps QPSK. FEC Rate 3/4 or 7/8 . Any data rate from 2.4 kbps to 2,460 kbps BPSK. Any data rate from 4.8 kbps to 4,920 kbps QPSK. Note: Maximum rates are limited using Reed-Solomon and IBS Multiplexer Options.
Settability  Any rate settable in 1 bit per second increments.
Data Clock Tracking Range > +/-400 ppm.
Data Rate Change Settling Time:  < 100 mSeconds.
Baseband Filter: Digital, n=6 Butterworth filter response.
Viterbi Forward Error Correction (FEC):  Viterbi convolutional decoder, k=7, Rate 1/2. G0 code = 171 octal, G1 code = 133 octal. Rate 3/4 or 7/8 using punctured code Rate 1/2 Coding Gain of 5.2 dB @ BER of 10-5 Rate 1/2 Coding Gain of 5.6 dB @ BER of 10-7
Turbo Product Codes FEC:  TPC Block decoder Rate 1/2 Coding Gain of 8.1 dB @ BER of 10-5 Rate 1/2 Coding Gain of 8.7 dB @ BER of 10-7
BER vs. Eb/No Performance:  0.2 dB typical over theoretical. 0.4 dB maximum.
Differential Decoding: Selectable On or Off.
Descrambler: IESS 308 or 309, Intelsat and V.35 selectable with enable @ Front Panel and via serial control port. IBS, Reed-Solomon and TPC specific modes are available when these options are installed.
Receive Data FIFO Buffering 4 bits to 131,070 bits, programmable in 1 bit Plesiochronous or Doppler increments or in time increments. The buffer is a Elastic Store 262,140 bit (maximum) self centering FIFO. Over or under-flow result in re-centering. When set to even multiples of the number of frame bits the re-centering minimizes frame disruption.
Buffer Output Clock Options  a. Receive Clock (disables buffer) b. Modulator Clock c. Internal Clock. Same rate as receive data rate clock setting, but accurate to 2 PPT at rate 1/2, or 4 PPT, rate 3/4 or 7/8, relative to either internal or external reference clock as selected. d. External Clock, input on data interface.
Electrical Power Requirements:
Prime Power: 90 to 260 Vac, 47-63 Hz, 50 Watts maximum