how to change signal with 1.8 V Peak to peak to digital sign

[abishek007]

v peak-to-peak

Hi all ,

I am i need of great favor . how to change signal with 1.8 V Peak to peak to digital signal 3.6 volts peak to peak .



Please do reply .

Thanks

Abishek Mann

 

[betwixt]

peak-to-peak voltage+signal

You can either restrict your digital range by using a lower ADC reference voltage, just digitize it and double the numeric result or a better method is to double the amplitude with a x2 analog amplifier then digitize it. The second method gives more resolution (accuracy) and costs very little more.

Exactly what circuitry you use depends on other factors, for example, what frequency is your signal, does it have a DC offset and does any part of the waveform pass below 0 volts.

Brian.

 

[abishek007]

how to vpeak

Hi Brain ,

Thanks a lot for the reply . I was curious to know if second solution will change if we are trying to change analog to digital signal on chip and on board . Also can we have 2 vdd's for analog portion of chip or analog portion on board .

Thanks,
Abishek Mann

 

[betwixt]

digital signal change

To double the signal you really need an amplifier outside the chip. ADC is a slow process so you can probably use an op-amp with its gain set to x2. You can use the same op-amp to remove DC offsets or to add an offset so negative going signals are kept above 0V.

I'm not sure what you mean by two vdd's, you can use the same supply for the op-amp as the rest of your design as long as the signal will fit within the output voltage swing of the chip. You will find some amplifiers cannot cope with a 3.6V swing while running on a low supply voltage. If that is the case, there is no reason why you shouldn't use a higher voltage for the amplifier provided the input to the ADC is not overloaded.

Brian.