Contract DSP software development

V.32 Modem Datapump

V.32 modem datapump implements 9600 and 4800 bit/s QAM modulation and demodulation according to ITU-T V.32 recommendations. Modem uses echo cancellation technics to provide full duplex operation over phone or 2-wire leased line.

V.32 features:
  • 16-bit 8 KHz sampled data
  • C API, Multichannel code
  • Optimized C code
  • PC test bench available
Mode was developed for TI 55XX DSP, porting to other DSP platform TI 54XX, 64XX, Blackfin and ARM is possible.

Official ITU-T recommendation V.32 is available at V.32 standard

V.32 development test bench

Commonly, test bench is used to simplify modem datapump development and simulate modem operation in non realtime mode. Test bench consist from two modem datapumps, channel simulator, generator and receiver of transmitting data or BER tester, command and configuration parser, sample/data read/write functionality, report generator etc.

Fully functional development test bench including source codes may be downloaded here V.32 testbench. Though test bench was used for described above modem development, V.32 datapump is excluded from freely available testbench and replaced with simple FSM modem V.23 from SpanDSP packet. Currently, documentation is available at Russian language only, source code comments written at english may be used instead.

Modem testbench is designed for MSVC 2008 Express and for Code Composer Studio 3.3 for TI 55XX DSP. Testbench C code is optimized with intrinsics, pragmas and other high level optimization technics. Modem testbench may be easily used at other TI DSP platforms 64XX and 54XX or ported to Blackfin, ARM etc.

Here is channel simulator diagram:
channel simulator diagramm

Channel simulator emulate following channel distortions:
  • Additive wight gaussian noise
  • Lineare distortions, attenuation and channel delay
  • Carrier offset
  • 2-nd and 3-rd order nonlinear distortions
  • Near and far end echo
Modem test bench can be easily modified for development phone line modems, fax modems, wireless HF modems etc.
  • Loop System Co. Ltd.
  • Improv Systems, Inc
  • 74ZE Engineering, Inc
  • Parabyte Co. Ltd.
  • Pulsar Group of companies
  • EasyPQ Technologies Pvt. Ltd.
  • NIC Test Electro
  • Telecomequipment