The application of a commutated filter to the design of a frequency response analyser

A new structure is discussed for a frequency response analyser incorporating a four-path filter to execute the correlation process. A detailed analysis of the filter is presented. The instrument covers the frequency range 10 Hz >f< 100 kHz and its advantages include higher frequency operation and increased dynamic range compared with previous designs and a voltage programmable sweep capability over a frequency range in excess of 1000 : 1.