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DVB-C demodulator / J83 demodulator

Product code: CMS0022

The CMS0022 Cable (QAM) Demodulator is fully compliant with the European, US and Japanese downlink cable standards DVB-C EN 300 429 and ITU J83 Annexes A/B/C (including DOCSIS 1.1/2.0). The core provides all the necessary functions between modulated QAM input to transport stream output.
J.83B designs can operate either from internal memory (short interleaving modes) or from shared external memory (long interleaving modes) by means of a versatile access controller.
Typical applications of the CMS0022 include head-end video and broadband data transmissions systems (CMTS), cable modem test equipment and point-to-point (PTP) or point-to-multipoint microwave radio links.
A range of synthesis options allows the core to be tailored for any particular application.


DVB-C demodulator / J83 demodulator DVB-C Standard

Block diagram

DVB-C demodulator / J83 demodulator block diagram (click to enlarge)
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Safari Plug-in

J83B 256-QAM ... safari plug-in (click to enlarge)
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Standards compliance

  • DVB-C EN 300 429
  • ITU J83 Annexes A/B/C
  • DOCSIS 1.1 / 2.0


  • Low demodulator implementation loss
    <0.2dB (16QAM), <0.4dB (256QAM).
  • IF sub-sampling or I/Q baseband input.
  • Wide carrier acquisition range.
  • Programmable symbol rate.
  • Large QAM support : BPSK .. QAM-256.
  • Variable ADC sampling frequency.
  • Automatic QAM mode, FEC and spectral inversion searching.
  • Pre-Viterbi and Pre-RS bit-error-rate statistics.
  • Post FEC bit-error-rate statistics.


  • ASICs for digital TV reception and cable modems.
  • Test and measurement equipment.
  • Transmodulator systems.
  • Point-to-point microwave transceivers.


  • Single external clock source.
  • Single external analogue AGC loop.
  • All-digital timing and carrier recovery.
  • Digital channel filtering.
  • Optimised for ASIC, Xilinx and Altera.
  • Evaluation boards available.