Designing multifrequency adaptive digital signals using symbolicaddition

摘要

Multifrequency testing by a microcomputer uses discrete intervalperiodic multifrequency test signals to interrogate a system with theaim of system identification in a non-parametric frequency responseform. It involves one multifrequent experiment which combines thetraditional monofrequent experiments. Data measurement, which is theprecision measurement analogy of data communication, allowsidentification coding theorems and symbolic operations to besuccessfully applied in the design of a variety of data measurementsignals. The three main symbolic operations are symbolic coding,symbolic phase shift keying and symbolic addition. In certain kinds ofexperiments the most suitable multifrequency test signal should beadapted so that the signal-to-noise-power-ratio at the output is thesame for each test frequency. Commonly the noise at the system outputhas a uniform power spectral density. This paper examines the use ofweighted symbolic addition of square waves in the design ofmultifrequency adaptive digital test signals for this situation. Theseprecision test signals have complementary multisymbol codes determinedby the DAC output levels