4 ms·
How do you implement the 1kHz filter? A 1kHz square wave is easily generated in software but surely you have to implement the filter using an op-amp and some pa
by barbegal 8y ago
How do you implement the 1kHz filter? A 1kHz square wave is easily generated in software but surely you have to implement the filter using an op-amp and some passives?
- wallacoloo 8y agoGiven it's a raspberry pi, you could easily implement the 1 kHz bandpass filter in software, by sampling at a higher frequency and then implementing a discrete-time filter. Just about any microcontroller with an ADC could do that, actually (edit: actually, the raspberry pi doesn't have an ADC - I guess the author is doing that with a discrete ADC?).
- barbegal 8y agoThe problem is that most micro-controller ADCs use sample and hold with a capacitor so they require some time to stabilise. From the source code of other projects this seems to be on the order of 1 to 5ms which effectively turns it into a low pass filter.