fft_accuracy_test

dt = 1e-6 #1MHz sampling
f_signal = 5e3 #5khz
SAMPLES_PER_PERIOD = 200
NPERIODS = 150

#Compute sinewave with relative accuracy:
t = range(0, dt, SAMPLES_PER_PERIOD)
sigT = 11.*sinpi(2*f_signal*t)
sig = zeros(SAMPLES_PER_PERIOD*NPERIODS)
for i in 1:NPERIODS
	sig[(i-1)*SAMPLES_PER_PERIOD+(1:SAMPLES_PER_PERIOD)] = sigT
end

Fsig = rfft(sig)

#Compute signal-to-noise ratio:
function SNR(Fsig, OSR=64)
	p = abs(Fsig[2:end/OSR]).^2 #Normalized pwr - DC excl
	S = maximum(p)
	N = sum((p .< S).*p)
	return 10*log10(S/N)
end

println("\nBase SNR w/64-bit arithmetic:")
@show SNR(Fsig)

:Done