Agilent Audio Analyzer - U8903A. Whether listening to mono, stereo or surround, the human ear knows what sounds good. Measuring how well, however, can be a challenge. The Agilent U8903A audio analyzer helps you measure and quantify audio performance in applications such as wireless audio, analog components, ICs, and consumer audio. Across the audio spectrum, this scalable, single-unit solution provides versatile measurement functions, diverse test signals and powerful analysis capabilities. Whatever is your application, the U8903A can help you make an audible difference in device performance. It can select generator, analyzer, graph and sweep modes with one-button access, measures at DC and from 10 Hz to 100 kHz, can characterize signal-to-noise ratio, SINAD, IMD, DFD, THD+N ratio, THD+N level, crosstalk, apply weighting functions, standard filters and custom filters, stimulate your device with high-quality signals and arbitrary waveforms, view numerical and graphical displays of measurement results, and can connect to a PC through GPIB, LAN and USB interfaces.

Multitone Test Signal. It consists of two or more sine waves. Using multi-tone signals, you can test a system at many frequencies at the same time. Many advanced telecommunications systems require multiple tones to be a part of the transmission mechanism, like ADSL. In consumer electronic, multiple tones testing is used in MP3 player testing.

IMD (Intermodulation Distortion). Distortion which is not harmonically related to the signal being amplified is inter-modulation distortion. It is a measure of the level of false signals resulting from unwanted combination of different frequency input signals. This effect results from non-linearity in the system. This feature is mainly used in electronic circuit design for speakers, amplifiers, and hi-fi systems.

DFD (Difference Frequency Distortion). This inter-modulation distortion test signal consists of two high frequency tones. The difference product of the two tones is measured relative to the signal amplitude. Normally use in measuring in-band 2nd and 3rd order inter-modulation distortion, useful in-band limited devices that cannot be easily measured using THD+N measurements.