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Electric Guitar Tuner Application Brief
The guitar tuner is implemented using either a uNet100(-1) or (-2) device depending on the host microprocessor type. A standalone implementation can be implemented using the (-3) version but would require an external analog to digital converter providing the frequency/phase input information. Input sampling of the frequency information is best obtained using phase sampling since this minimizes the amount of samples to evaluate. Additionally, the presence of higher order harmonics resident within the guitar output spectrum are best handled this way. The limitations of the tuner application are the 20KHz sampling rate used in differentiating between closely spaced string frequencies. A complete tuner would include: instumentation amplifier, low pass filter and logic level buffering to boost input signal amplitude to TTL (+5/0VDC).
File List:
- Spreadsheet calculates phase sampled values for various combinations of sampling rate and guitar string frequency. Equations are provided for either fundamental only or fundamental combined with 2nd harmonic component phase shifted 0,45,90,135 degrees phase with respect to the fundamental. These combinations are useful in simulating the spectrum produced by an unfiltered guitar string.
NetBuilderLite Fundamental Training - Training and testing vectors to build feed forward network to detect fundamental frequency component. This file also demonstrates general design method for training networks in detecting spectrum components.
NetBuilderLite 2nd Harmonic Training - Vector sets for detecting fundamental and 2nd harmonics generated by unfiltered guitar strings.
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