This Digital Signal Generator will be of immense use to the following categories of people:
* Computer Sound Card Design Engineers or hobbyists wishing to measure or check the specification of their Audio Sound outputting cards.
* Manufacturers and hobbyist makers of TEST CDs.
* Those wishing to create accurate sound samples for use in other programs.
* The curious eager to learn more about FFT's, probability density, and digital signals.
* Service Engineers servicing HiFi and CD players.
Waveforms - Sine, Square, Triangle, Sawtooth, Random Noise, Pink Noise, Sin/Cos quadrature, two-tone IM distortion, TDF 0.8 + 1.195 kHz, TDF 8 + 11.95 kHz, Delta Function, J-Test.
Random Noise Probability Distribution - Gaussian With Crest Factor=4, Triangular, Square, Haversine, Parzen, Welch and others.
Amplitude +12dB, +10 dB, +9dB, +7dB, +6 dB, +5dB, +4dB, +3 dB, +2dB, +1dB, 0dB, -1dB, -2dB, -3dB, -4dB, -5dB, -6dB, -7dB, -8dB, -9dB, -10dB, -20dB, -30dB, -40dB, -50dB, -60dB, -70dB, -80dB, -90dB, silence
Reference Level - 0dB fsd, -15dB fsd, or -18dB fsd to simplify setting of dBm0s. Plus 0dB, -0.1dB, -0.2dB, -0.3dB, -0.4dB, -0.5dB, -0.6dB, -0.7dB, -0.8dB, -0.9dB, -1dB, -2dB, -3dB, -4dB, -5dB, -6dB, -7dB, -8dB, -9dB, -10dB to simplify setting of small values of Amplitude
Dither - OFF - or ±2 lsb peak to peak dither with either Gaussian, Square or Triangular pdf.
Decay Time - 100 ms, 200 ms, 300 ms, 500 ms, 1 second, 2 seconds, 3 seconds, 5 seconds, 10 seconds. (60dB 'reverberation' decay).
Tone Burst - using any of the FFT window functions (Square (none), Gaussian, Triangular, Hanning, Cos Taper, Cos2, Welch & Parzen)
Modulation - AM and/or FM, using three different Modulator Waveforms (Sin, Square and Tringular), a selection of Modulation Depths from 0% to 200%, and a selection of Modulation Frequencies (1Hz to 5kHz). The modulation acts on all Waveforms except Sin+Cos. On Sin+Cos only phase setting or phase modulation is available. The modulator section also includes waveform modifiers, or waveform distorters of various kinds. [Modulation only available on 1600x1200 mode version]
Sample Frequency - standard audio frequencies for DAT & CD - 32 kHz, 44.1 kHz, 48 kHz including the new 96 kHz CD standard.
Frequencies - All ISO standard third-octave frequencies from 10 Hz to 20 kHz (to 40kHz at 96 kHz sampling frequency). That is 10, 12.5, 16, 20, 25, 31.5, 40, 50, 63, 80, 100 and their decade multiples). Selectable between ISO R266 exact or ISO R266 nominal.
Frequency Sweep Range - (LOG sweeps) 0.1 times, 0.2, 0,5, 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000 and 2000 times. Plus third octave and octave sweep. Random noise cannot be frequency swept.
Dynamic range and Signal to Noise ratio of saved files - 96dB or -93dB with dither (un-weighted) [-66dBnom]
Amplitude Accuracy - 16 bits (± 0.002% fsd, or 0.0002dB fsd).
Frequency Accuracy - 30 bits fsd (WAV files) [but dependant upon CD-R recorder Xtal frequency accuracy or computer DAC Xtal frequency accuracy]
Distortion - (0.0016% at full output with dither)
Probability Density Distribution Graph
No of Bins of PDD graph - 128 (at 16-bit D/A resolution)
FFT Plot - see FFT plot.
Hi-Fi Test CD