Dsp Nominal Signal Level For Audio Line IN?

Wireless & IoT
1

Hi i have a question about the minimum and maximum voltage level that my DSP receiver must take. So i have a wireless system .The dsp reveiver take a signal that is downoconverting to 10khz around…

http://i1284.photobucket.com/albums/a57 … 361020.png

i found the integrated that make the ADC and DAC . is is AIC23 CODEC

http://www.ti.com/lit/ds/symlink/tlv320aic23b.pdf

at page 2-2 i read that: Line Input to ADC Input signal level (0 dB) 1 V RMS

at page 2-1 says about the supplies i don’t know if it helps

so to work with efficiency i must feed this DSP with 1 V (rms).

if i feed it with 0.5 or 1.5 maybe more BER comes ?

2

From 3.2.1 of the TI data sheet:

The ADC full-scale range

is 1.0 VRMS at AVDD = 3.3 V. The full-scale range tracks linearly with analog supply voltage AVDD. To avoid distortions,

it is important not to exceed the full-scale range.

There is also settable gains so a smaller signal can be gained. But if a larger signal then its peaks get clipped and thus distorted.

Does TI have any additional App Note on this chip? or for the chip family?

3

waltr:
From 3.2.1 of the TI data sheet:

The ADC full-scale range

is 1.0 VRMS at AVDD = 3.3 V. The full-scale range tracks linearly with analog supply voltage AVDD. To avoid distortions,

it is important not to exceed the full-scale range.

There is also settable gains so a smaller signal can be gained. But if a larger signal then its peaks get clipped and thus distorted.

Does TI have any additional App Note on this chip? or for the chip family?

Thanks for the reply :smiley: !

So the input to ADC depends aproximattely on the AVDD of the ADC. Based on 3.3Volt it is 1 VRMS.

The minimum AVDD=2.7 VOLTS so the minimum analog voltage input how can it be ?About 0.7rms maybe.

I have already an active filter before DSP receiver but the gain is not capable to work efficiently the ADC.(i give only 35mV rms.)

So i will make an non-inverting oper.amp with potentiometers ?will it work? my signal’s bandwidth is 14Khz

4

An external amp should work.

But what about the internal Gains? I didn’t read in detail about these but you should and maybe even experiment to see if your 35mVrms is a problem or not before adding the amp.

5

waltr:
An external amp should work.

But what about the internal Gains? I didn’t read in detail about these but you should and maybe even experiment to see if your 35mVrms is a problem or not before adding the amp.

at the time i don’t have change the internal gain.it is in the default.so o dB. if i put the maximum 12dB=>

Vout=4Vin. so

vOUT=4*35mvrms=140mvrms= 0,14 VRMS. it is again too low as i understand.

and op.amp needs i think… :geek:

I am still not sure about the minimum voltage level to work effiently… :?: :?: :?: :?: