Multi-Instrument is a powerful multi-function virtual instrument software. It supports a variety of hardware ranging from sound cards to proprietary ADC & DAC hardware such as NI DAQmx cards. Functions includes: (1) Oscilloscope: Dual-trace waveform, waveform addition, subtraction & multiplication, Lissajous pattern, signal recording, digital filtering, AM/FM/PM demodulation, reverberation & speech intelligibility analysis. (2) Spectrum Analyzer: amplitude spectrum, octave analysis (1/1~1/96), frequency compensation, frequency weighting (A,B,C,ITU-R 468), peak hold, linear/exponential average, measurement of THD, THD+N, SNR, SINAD, Noise Level, IMD, Bandwidth, Crosstalk, peaks, harmonics, TD+N, DIM, Wow & Flutter, sound quality, phase spectrum, linear or circular auto/cross correlation, coherence function, transfer function, impulse response. Support 60 window functions. (3) Signal Generator: function/multitone/arbitrary waveform/burst tone/MLS/DTMF/musical scale/white noise/pink noise generation, frequency/amplitude sweep, fade in/out, AM/FM/PM modulation. (4) Multimeter: RMS voltage, sound pressure level (dB, dBA, dBB, dBC), frequency counter, RPM, counter, duty cycle, F/V converter, cycle mean/RMS, vibrometer. (5) Spectrum 3D Plot: waterfall and spectrogram, supporting both Short-Time Fourier Transform and Cumulative Spectral Decay. (6) Data Logger: long time data logging function for tracing up to 64 derived variables such as RMS. (7) LCR meter: It is used to measure the value of an inductor, a capacitor or a resistor, or the impedance of a network of them. (8) Device Test Plan: It provides a mechanism to configure and conduct device test steps. It takes the advantage of the sound card’s (or other ADC/DAC device's) capability of simultaneous input & output, to generate a stimulus to the Device Under Test (DUT) and acquire its response at the same time. Different stimuli can be generated and the response can be analyzed in different ways.