Hi.
I was thinking about building an ultrasonic sinusoidal "chirping rangefinder"/"doppler speed-measure-thingy".
All of the circuits I have found drive the transducer with a square wave which won't allow nice tone generation for chirping or doppler measurement. I have a feeling this is more akin to audio drivers which I don't know much about.
I was thinking about driving the transducer (electrostatic/capacitive) with a
DSP->DAC->amplifier->matching transformer->transducer
Is this the right way to go about the driver? I heard some mention of "biasing" capacitive transducers, although I don't know why you would need to bias a speaker...wouldn't that just limit it's dynamic range?
For the receiver, I was thinking
transducer->transformer->amplifier->ADC->DSP
And then having the DSP do some fourier analysis on the whole thing. Am I on the right track with this?
Since I want an sample rate of 16x the max frequency (60kHz), with 8-bit resolution and the maximum wait time is 0.04s, I need about 40k of memory to store all the numbers while the DSP runs through the signal processing. Not sure how long it would take for a DSPIC. To do a fourier analysis of 40,000 data points.
Thanks.
I was thinking about building an ultrasonic sinusoidal "chirping rangefinder"/"doppler speed-measure-thingy".
All of the circuits I have found drive the transducer with a square wave which won't allow nice tone generation for chirping or doppler measurement. I have a feeling this is more akin to audio drivers which I don't know much about.
I was thinking about driving the transducer (electrostatic/capacitive) with a
DSP->DAC->amplifier->matching transformer->transducer
Is this the right way to go about the driver? I heard some mention of "biasing" capacitive transducers, although I don't know why you would need to bias a speaker...wouldn't that just limit it's dynamic range?
For the receiver, I was thinking
transducer->transformer->amplifier->ADC->DSP
And then having the DSP do some fourier analysis on the whole thing. Am I on the right track with this?
Since I want an sample rate of 16x the max frequency (60kHz), with 8-bit resolution and the maximum wait time is 0.04s, I need about 40k of memory to store all the numbers while the DSP runs through the signal processing. Not sure how long it would take for a DSPIC. To do a fourier analysis of 40,000 data points.
Thanks.
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