Telemetry Card & Modular Interface Products

Model 674DM 40 Mbps Advanced Dual PCM Bit Sync Mezzanine

The 674DM Advanced Digital PCM Bit Sync is a state-of-the-art compact “mezzanine” design that provides a cost effective and modular high quality bit sync add-on to Acroamatics entire line of single slot PCI single card TM processing card products.

The 674DM is compatible with existing legacy and our latest telemetry card components. Based on our 3rd generation bit sync design, it shares the latest techniques in FIR filtering, digital phase-locked loop, NCO clock reconstruction, and digital amplitude and offset control with its larger PCI cousin, the Model 1611P. Incorporating a leading-edge FPGA, this modern design delivers a significantly reduced parts count, improved reliability, and expanded capabilities – including options normally found only in box level and multi-card bit sync/encoder designs. The 674DM supports options such as Frame Sync Pattern Verification, BERT, PRN and programmable PCM simulator, and Convolutional encode/decode.

The Model 674DM PCM Bit Sync is fully compatible with legacy Acroamatics TDP system and remote Bit Sync utility software set-ups, easily meeting and exceeding all IRIG performance and functional requirements.


    Two Independent Bit Syncs
  1. Mounts to 1632AP PCIe Dual Decom
  2. Multiple Program Controlled Inputs and Outputs
    Tunable Bit Rate Range
  3. 8 bps to 40 Mbps, all codes
  4. Best in Class Noise Performance
  5. within 0.50 db of theoretical
  6. Fast sync acquisition
  7. within 50 bit transitions, typical
  8. Best in Class Sync Retentiont
  9. to 1024 bits without transition
  10. Data Quality and Signal Test:
  11. BERT / PRN BER Link Test Mode
  12. Frame Sync PCM BER Monitor
  13. Frame Lock/Loss Monitor
  14. Eb/No Signal Quality Output
  15. Viterbi Error Monitor / Stats
  16. Data Simulator/Generator

  17. Processes all IRIG Codes
    Remote Software Operations

    GUI Setup and Operation status of all Acroamatics Bit Synchronizers are controlled via a single interface, with drop down menus for individual cards. The software automatically recognizes all available bit synchronizers, as well as their features.

    Up to 20 unique setups are stored and available for instant bit sync configuration, supporting from one to 64 bit syncs apps.


Two (2) Inputs, Operator Program selectable, per Bit Sync Channel (Direct to companion decom & external)
Greater than 60dB at 20MHz
Program selectable: Hi-Z/Lo-Z, Single Ended: 4kΩ /75Ω (std) or differential: 150 Ohm or Hi-Z (opt)
Signal Level
0.2 to 20V p-p, Single-ended. Differential: 0.2 to 10V p-p, Differential (optional)
DC Offset
20V max Single-Ended, Hi-Z or 15V Max @ 75Ω
Baseline Variation
Tracks sinusoidal offsets to 100% p-p signal amplitude at 0.1% bit rate
PCM Codes
Program selectable: NRZ-L/M/S, Biø-L/M/S, DBiø-M/S, DM-M/S, MDM-M/S, RZ
Program selectable: RNRZ 9/11/15/17/23, forward/reverse


Bit Rate Range
8bps to 40MHz, all PCM Codes
Tuning Resolution
0.1% of bit rate
Capture Range
3 times the programmed loopwidth, typical
Tracking Range
±12% typical, with programmable limiter
Loop Bandwidth
0.1% to 3.2%, program selectable in 0.1% increments
Sync Threshold
0db for NRZ-L and Biø-L codes
Sync Maintenance
(LW=0.1%) –2dB NRZ-L and Biø-L codes
Sync Acquisition
(LW=1.6%, SNR > 12dB) Typically less than 50 bit periods
Sync Retention
(LW=0.1%, SNR > 3dB) Retains sync through > 1024 consecutive dropouts
Bit Error Rate
(LW=0.1%) to within .50 dB of ideal bit error rate performance curves


NRZ-L Data
One each, NRZ-L data/clock pair, RS422/TTL (jumper selectable) - operator program output selectable to INTERNAL (direct to host decom card via internet bus) or EXTERNAL (output pair directed to card external output BNC or Triax cables)
Data Clock
0°, 90°, 180°, 270°, operator program selectable
Data Polarity
Program selectable: normal/inverted

DATA/CLOCK OUTPUTS, CODE (Dual PCM Encoders) Per Bit Sync

Data Source
Program selectable: Recovered Data (Bit Sync NRZ-L Data/Clock - DEFAULT) or External Data/Clock (PROGRAM SELECTABLE).
Three each: One each TTL data/clock (0° & 180° selectable) Code (selectable) PCM and Clock, One each TTL data RNRZL, One each TAPE (code selectable) TTL or ±2 Volts balanced output, 50mA drive current.
Program selectable: RNRZ 9/11/15/17/23, forward/reverse
PCM Codes
Program selectable: NRZ-L/M/S, Biø-L//M/S, DBiø-M/S, DM-M/S, MDM-M/S, RZ


Signal Type
Jumper selectable: RS-422 or TTL
120Ω , RS-422, 75Ω TTL
Data Code
Program selectable: NRZ-L/M/S, Biø-L/M/S, DBiø-M/S, DM-M/S, MDM-M/S, RZ
Data Clock
Program selectable: Normal/Inverted, 1x or 2x


Viterbi Decoder
Rate 1/2, k=7: includes differential decoding, V.35 descrambling, and G2 invert (others available)
Symbol Formats
Serial, parallel, and staggered parallel (others available)
Convolution Encoder
Rate 1/2, k=7: includes differential encoder, V.35 scrambler, and G2 inverter (others available)
Symbol Formats
Serial, parallel, and staggered parallel (others available)


Format Generator
Programmable frame length, sync pattern and mask
Synchronizer Source
Recovered data, external data or test generator
Synchronizer Strategy
Pattern match in "search", programmable error limits for "check" and "lock" states
Other Features
Bit slip enable, auto polarity enable, data source/ambiguity resolution


Transmitter Pattern
PRN sequence: PN7, PN9, PN11, PN15 (forward/reverse)
Pattern Clock Source
Program selectable: Bit Rate Clock or External Clock
Program selectable: 64, 128, 256 bits
BER Sample Period
Program selectable: 1E3 to 1E9 bit periods, or continuous accumulate
Variable Output
50mV to 5V P-P
Other Features
Automatic pattern sychronization, forced error ON/OFF


Hosts Supported
Plugs onto Models 1611P, 1626P, 1612P, & 1622P (PCI), 1632AP (PCIe), or RS232 Standalone
Cooling Requirements
30 Linear FPM
Power Requirements
+5VDC @ 1.25A, ±12VDC @ 0.25A
6.5" (16.51cm) H x 4.0" (310.16cm) W x .625" (1.5875cm) D
Operating: 0° to +40° C, Non-operating -40° to 86° C
Relative Humidity
Up to 90% non-condensing
Operating 6G, Non-operating 25G
Operating 0.3G, 5 to 2000 Hz, Non-operating 0.8G, 5 to 500 Hz

Specifications subject to change without notice.