Unknown Sampling Frequency

Question

If somebody gives me a waveform and its highest frequency is unknown to me then how would i determine the sampling rate of the given signal?

Answer 1

If you don't want aliasing, the sampling rate should be above twice the start of the high frequency stop-band of whatever filter you can find to use before the sampler.

The physics of the environment in which the waveform resides will often provide its own low-pass or band-pass filtering (propagation loses, transducer loses, etc.). If you can determine the cutoff of this natural filter such that its stop-band is below your desired noise floor, you can use greater than 2X this frequency.

If you don't care about aliasing, then any sample rate will do, but the lower the frequency, the smaller the bandwidth of the result and the greater the multiple of layers of aliasing within that bandwidth.

Answer 2

I would simply listen to the wav file at different sampling rates and look for the sampling rate at which it sounds natural.