Automatic Gain Control required for Dual Tone Multiple Frequency (DTMF)

Aravind Chakravarti

Other Parts Discussed in Thread: LM13700

Hi,

I would like to know if Texas Instruments has any IC that can provide AGC ('Automatic Gain Control') functionality for DTMF (Dual Tone Multiple Frequency) input signal.

We need AGC specifically for DTMF tones because DTMF tone has Unique envelope which makes harder for AGC to retain envelop at the output.

If required we can provide any attenuation or gain to DTMF signal to match ICs characteristics. And we do not need any DTMF decoding functionality. We have very specific requirements for DTMF decoding and we already have a solution for that. (We just need an AGC)

If someone thinks that we can use normal AGC for DTMF decoding, please provide a rough architecture with specifying important ICs.

Thanks & Regards,

Aravind D. Chakravarti,

Bangalore

over 6 years ago

0 Ron Michallick over 6 years ago

TI__Guru*** 148256 points

Hello Aravind,

LM13700 has a programmable gain based on a DC current and load resistance and there are AGC examples in the data sheet.

Alternatively, a logarithmic amplifier could be used to compress the signal so that AGC might not be needed.
www.ti.com/.../products.html

0 Aravind Chakravarti over 6 years ago in reply to Ron Michallick

Intellectual 530 points

Hi Ron,

Thank you very much for providing ideas. Give me some time. I will go through with the AGC and Logarithmic amplifiers. I will try to simulate few things first.

If anything required, I will get back to you.

Thanks & Regards

Aravind

0 Ron Michallick over 6 years ago in reply to Aravind Chakravarti

TI__Guru*** 148256 points

Aravind,

I'll mark this thread as resolved. Create a new post once you have a part number so the engineer supporting that device can respond. If you have a follow up question you can still respond to this thread.

There are also high frequency programmable and variable gain amplifiers in this product list.
www.ti.com/.../products.html

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Automatic Gain Control required for Dual Tone Multiple Frequency (DTMF)