Digital noise generator.

摘要

A digital noise generator for use in aeroengine noise testing can accurately and repeatably reproduce a standard noise spectrum so that differing noise analysis systems can be cal. ibrated to a common standard. The noise generator comprises a pseudo-random binary sequence generator (2) which is fed with a low clock frequency derived from a high frequency crystal oscillator (14). The generator (2) produces a pseudo-random noise single bit signal which is fed to the most significant bit input of a digital to analogue converter (8), whose other inputs are fed with simulated tone data residing within an EPROM (6), the pseudo-random and tone noise thereby being digitally summed before conversion to an output analogue signal of desired spectral characteristics.