Transfer function measurement

[jordens]

Components:

• log swept sine modulator for the signal generator Scan mode #86 Sweptsine #965
• streaming of stimulus and response data to host Adding data livestream capability #380
• host processing and analysis: impulse response, non-linear impulse responses
• also applies to Thermostat (_EEM) add sweptsine generator thermostat-eem#194

Options:

• alternatively have a fully analytic correct host side stimulus reconstruction (no stimulus streaming)
• on-device analysis: needs FFT, may need logarithmic/decade decimation
• compensate the transfer function with biquad

Some background:

• https://www.thinksrs.com/downloads/pdfs/applicationnotes/SR1_SweptSine.pdf
• http://www.four-audio.com/data/MF/aes-swp-english.pdf http://melaudia.net/zdoc/comparisonMesure.PDF
• https://hal.archives-ouvertes.fr/hal-02504321/document
• http://jenshee.dk/signalprocessing/sweepmeas.pdf

[jordens]

dual-iir loop-back, gain 1, 9.99 V amplitude, batch size 8 (8 ADC, 8 DAC), 18 sample delay subtracted, first five orders are blue, orange, green, red, violet, low-f leakage into higher orders and high-f spurs are artefacts, floor due to quantization sincos is around -130 dB.