Methods to design op amp ciruits?

[jose_peeterson]

hmm...

I don't understand something! Why is the RC feedback network in stage 1 doing High pass filtering and RC feedback network in stage 2 doing Low pass filtering? should not they both do one thing only and the series RC network in stage 2 at the inverting input do the other (HP or LP)?

 

[FvM]

The difference is in charge versux acceleration transfer characteristic of the sensor, demanding for charge sensitive amplifier. The CSA uses an integrator topology (feedback capacitor) to achieve a frequency independent transfer characteristic. A parallel resistor creates a highpass cut-off frequency.

The CSA structure is already suggested in the Murata datasheet, by the way.

 

[jose_peeterson]

I have just got a better model of the shock sensor but I cannot get any output. I believe the transformer is causing the problem. I am supposed to get a AC output with stepped down voltage I guess?

The L1 and L2 values of the transformer are are 1H and 42.8uH. K = 0.99, M = 6.4767m. These values are specified by the manufacturer. Why is the output still 0 dc.

THANKS.

 

[FvM]

Either Murata didn't give a clear specification of the model input/output scaling, or you didn't understand it. I believe that the equivalent circuit intends to model the sensor characterictic, but the output signal is very low, in a mg range referring to sensor sensitivity,

It's also not quite clear what you want to achieve with the sensor model.