multi-instrument is a powerful sound card based multi-function virtual instrument software. it supports sophisticated triggering method including pre-trigger and post-trigger,level trigger and differential trigger. it supports 8, 16, 24 bits. a comprehensive range of functions are provided, including: (1) oscilloscope: dual-trace waveform, waveform addition and subtraction, lissajous pattern, transient/long-time signal recording, voltmeter. various digital filters are supported. (2) spectrum analyzer: rms amplitude spectrum, relative amplitude spectrum, octave analysis (1/1,1/3,1/6,1/12,1/24), frequency compensation, frequency weighting (a,b,c,itu-r 468), peak hold, averaging, measurement of thd, thd+n, snr, sinad, noise level, imd, bandwidth and crosstalk, phase spectrum, auto correlation function, cross correlation function, coherence function, transfer function, impulse response. support 55 window functions and window overlap. (3) signal generator: function generation, multitone generation, arbitrary waveform generation, burst tone generation, mls generation, dtmf generation, musical scale generation, white noise and pink noise generation, and frequency/amplitude sweep. synchronized operation between the signal generator and the oscilloscope is supported. (4) multimeter: voltmeter, sound pressure level meter(db, dba, dbb, dbc), frequency counter, rpm meter, counter, duty cycle meter, f/v converter. the counter trigger level and hysteresis can be adjusted. (5) spectrum 3d plot: including waterfall and spectrogram. (6) data logger (7) lcr meter (8) device test plan: device test plan provides a mechanism for you to configure and conduct your own device test steps. it takes the advantage of the sound card’s capability of simultaneous input & output, to generate a stimulus to the device under test (dut) and acquire the response from that device at the same time.