free spectrum analyzer

Linrad - Multiplatoform freeware DSP software. Linrad has its origin in software that was developed for 144 MHz EME CW but it is quite general and should be seen more like a kit for designing a receiver that a receiver for some particular usage. It can be used as a CW receiver with a small time delay and a fast waterfall graph. A dsp for conventional receiver to imporve signals readability, a spectrum analyzer.

Spectrum Analyzer Real-time FFT - Eight-channel Audio Spectrum Analyzer is a set of Real-Time Multi-Channel Gauges for investigation of data accepted from any ADC you will want or 16-, 24- and 32-bit ADC of sound card. WDM drivers support. FFT Spectrum Analysis, OscilloScope, Frequency counter, AC/DC voltmeter, Signal-to-Noise Ratio, Signal-to-Noise and Distortion, Spurious-Free Dynamic Range, Effective Number Of Bits, Total Harmonic Distortion, Inter-Modulation Distortion, Phase Shift. Special modes of dual-channel FFT spectral analysis: Separate channels spectra, Spectra of digital sum, difference, product of two signals, Spectrum of digital product of original signal and its fundamental, Spectrum of Real and Complex Transfer Function, Cross Spectrum. Standart weighing of spectra according IEC and CCIR. Oscilloscope modes (for dual-channel ADC) are: original signals, sum, difference, dependence of one channel on another, amplitude distribution of input signals.