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ISDB-T modulator

Product code: CMS0045

The ISDB-T modulator / ISDB-TB modulator core enables rapid development of audio and visual systems using commodity free-to-air set-top-box products. Commodity products have largely been aimed at the broadcast market where the high volumes are at the demodulation end of the link. The Commsonic ISDB-T modulator allows exploitation of this technology by allowing the development of the ISDB-T modulator in low-cost FPGA or ASIC implementation. Applications include CCTV, wireless home networking, test equipment, etc.
This core is intended to provide a very efficient FPGA or ASIC implementation of all functions required to take the output from one, two or three MPEG-2 transport multiplexers and modulate it according to the ISDB-T ARIB STD-B31. The specification is fully supported by the ISDB-T modulator for 2K, 4K and 8K COFDM modes as well as hierarchical transport streams. The standard output is a baseband I/Q digital pair for direct connection to a DAC. Alternative output configurations include a low IF, direct connection to standard Analog Devices Direct Digital Synthesizers (e.g. AD9857), or Analog Device RF DACs (e.g. AD9789).
The ISDB-T modulator / ISDB-TB modulator targets SDRAM for minimum cost but also supports synchronous SRAM or internal FPGA RAM, allowing flexible implementation on a range of platforms.
Every effort has been made to keep the size of the ISDB-T modulator / ISDB-TB modulator to an absolute minimum in order to target the low-cost FPGA families, however this has not been at the expense of functionality. Synthesis directives are used wherever possible to remove blocks within the design which contain functionality not required for all applications.


Block diagram

ISDB-T modulator block diagram (click to enlarge)
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Safari Plug-in

ISDB-T modulator safari plug-in (click to enlarge)
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Standards compliance

  • ARIB STD-B31
  • ABNT NBR 15601


  • RS and convolutional encoding.
  • Partial reception segment encoding.
  • Supports SDRAM or synchronous SRAM.
  • Time and frequency interleaving.
  • (D)QPSK, QAM-16 and QAM-64 support.
  • Hierarchical layer support.
  • 2k,4k and 8k FFT.
  • FFT guard interval insertion.
  • Optional FFT output windowing.
  • Optional critical-mask output filter.
  • Optional PID filtering.
  • Optional Packet insertion.
  • External AD9857/AD9957 DDS interface.
  • Automatic AD9857/AD9957 programming.
  • External AD9789 RF DAC interface.
  • Automatic AD9789 programming.
  • Optional AD9516/ADF4350 PLL programming.
  • Optional internal IF conversion.
  • Optional in-band equalisation.
  • Optional CPU-free configuration.


Plug-ins / Extensions