speech codec IC

Hello All,

I need a help here.
Iwant to process a voice signal from telephone line (single channel)
so that it can be processed digitally.
What speech codec ic should I use for this application.
Thank you for your kind help

Regards,

Novan

See this thread you can see some useful links on that regarding ISD chips.

https://www.electro-tech-online.com/threads/what-is-that-secret-voice-recorded-ic.29861/

The Si3000 has been pretty good. It is a high quality 16-bit mono voice codec in a reasonable pkg to solder. It has on-board Programmable Gain Amplifiers and lots of neat stuff. You do not need to do any input or output filtering to remove components above the normal 4KHz voice range.

Its output format is a bit difficult to use unless you have a DCI or Framed SPI port. The dsPIC33/30 or PIC24 have them, and those are also 16-bit cores so they handle the data words well. The PIC18F series, not sure if the SPI could be configured to read in, in which case you're out of luck.

The dsPIC30-33 series also have a software "Speex" encoder/decoder to compress voice down to 1KB/sec. It can compress and decompress on the fly.

I have a ready-to-go driver project to interface 1 to 3 Si3000 devices with a 33F using the DMA controller. DMA controller is nifty, allows the module to fill a buffer without interrupting the core and can even operate when the core is in SLEEP.

Oznog said:

The dsPIC30-33 series also have a software "Speex" encoder/decoder to compress voice down to 1KB/sec. It can compress and decompress on the fly.

Click to expand...

I have been impressed how inexpensive the microchip microcontrollers are. You can get the DSPIC30F4013-30I/P for less then $7. 30 Mips, 48K Flash, 2k RAM, and 12 bit ADC, If that is not enough for $11 you can get the dsPIC30F6014A with 144K Flash and 8K of RAM. Free compiler.

Sounds fun. One more thing for the idea/todo list. Makes me

The 33F is in many ways better.
The 30F in the small pkg requires so much current at high speeds, and also requires 5V at high speeds, that it will actually burn itself up if you don't put a heatsink on it.

The 33F is faster and runs on a small fraction of the power. 3.3V max part though. Has a 5v compatibility on some pins.

The 33F also has that nifty DMA controller.