Frequency Response of a HW Rectifier

[magnetra]

hw-retifier

I am modeling the audiotary system of mammals. In the model I have a half wave rectifier block. I need to develop frequency response of the rectification action. How do I go about that? Can any one give me a lead?
I tried to compare the Fourier Series coefficients of input and output for a simple sine wave rectification, but could not come up with anything useful.

Thank you

M

 

[biff44]

h-w controlled rectification

I assume you mean a DSP function that is a half wave rectifier. But in the real analog world, a half wave rectifier has a freqeuncy response that is selectable by the designer. THis is because there are two parts to a physical half wave rectifier: 1) something that rectifies a sine wave to become a series of one-way current pulses (usually a diode), and 2) something that integrates (or stores) those rectified current pulses (usually a capacitor). The diode has a series resistance, so there is a R-C time lag in charging up the capacitor, and the capacitor has a load resistance across it, so there is another R'-C discharge time in the capacitor voltage drooping after the sine wave input goes away.

So, simplistically, a half wave rectifier can be thought of as a rectifier with a lowpass filter response. More precisely, it can be thought of as a rectifier with different rise and fall times--both user controlled.

 

[FvM]

Basically, a halfwave-rectifier is a nonlinear circuit, while frequency response is a linear prperty in circuit theory. So my general simple answer is: It has none!

Obviously, the auditory system is exposing nonlinear effects at high sound pressure levels, but it's surely linear at low levels. Thus I don't expect that the said rectifier is an appropriate model for the main signal path. It may be a means to model non-linear effects in a parallel path.

P.S.: If you refer to the frequency selective sound level detection in the inner ear, the detector could be possibly thought as a rectifier. It may be characterized with a response and a decay time. But it has nothing to do with fourier series. It has a frequency response related to the signal envelope rather than the original signal.

 

[xulfee]

it is non linear device