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SRC Quality
This document not yet complete. When measuring the performance of a Sample Rate Converter, there are three factors to consider:
There are a number of sample rate converters available for downloading but I will limit the comparison ot Secret Rabbit Code to the following:
MethodologyMeasuring the SNR of a converter is relatively straight forward. Generate an input signal consisting of a windowed sine wave, sample rate convert it and measure the signal-to-noise ratio of the output signal. A typical length for the original file is 20000 samples. The bandwidth of a sample rate converter is much more difficult to measure. Currently this is done by generating a file containing many short (approx 1000 samples) sine wave bursts separated by silence. The sine wave bursts a evenly spaced between 0.75 times the sample rate and 0.95 times the sample rate. This file is then processed and analysed to determine the bandwidth of the converter. The speed of a sample rate converter is easy to measure; simply perform a conversion on a large file and time the conversion process. SoXSoX provides three methods of resampling; a linear interpolator, a polyphase resampler and the Julius O. Smith simulated analogue filter method. ShibachShibach More Coming Soon. |