AD-converter

[lovechild]

Hi, can anyone please help me in solving this question,

Design an operational amplifier circuit for a signal conditioning application,where the signal of a microphone is conditioned for an AD-converter.
-Microphone signal peak-to-peak value is 122mv.
-Microphone signal has zero-bias, i.e itvaries equally on both sides of zero
-Microphone output impendance is 600 Ohms
-AD-converter has 0 V to 2.5 V input voltage range
-AD-converter has a 2.5 V reference voltage output on chip,which you can use in biasing circuit
-AD-converter input impendance is 10 KOhms
-The total signal attenuation on the system should be less than 1% ( = 99% of the optimal signal strengh remains)


2.design an anti-aliasing filter for the previous application taking into account the following requirement and properties:
-the application requires that the signal power spectrum has minimal amount of spectral distortion
-signal information bandwidth is 122Hz
-signal has white noise at level -40dB
-sampling rate is 444100s-1
-AD-converter's resolution is 12 bits
thnks in advance

 

[Roff]

You need to post specs for the A/D converter - input voltage range and input impedance.

 

[lovechild]

hi thanks Ron ,sorry about that, they are ;

-AD-converter has 0 V to 2.5 V input voltage range
-AD-converter has a 2.5 V reference voltage output on chip,which you can use in biasing circuit
-AD-converter input impendance is 10 KOhms
-The total signal attenuation on the system should be less than 1% ( = 99% of the optimal signal strengh remains)

 

[Someone Electro]

You need to take half of the 2,5V reference as a virtual ground in a standard opamp amplifier circuit with a capacitor between the mic and its input. The gain of the amplifier must be around 40 (I suggest making the gain adjustable using a trimmer resistor)

 

[Roff]

You need to take half of the 2,5V reference as a virtual ground in a standard opamp amplifier circuit with a capacitor between the mic and its input. The gain of the amplifier must be around 40 (I suggest making the gain adjustable using a trimmer resistor)

A gain of 40 would give almost 5V p-p. The A/D is 2.5V full scale.

 

[Someone Electro]

Oh right i missed that one its supposed to be 20. Sorry