Phase—synchronous–type walsh analyzer using switched—capacitor circuit
Itsuo Sasaki, Shojiro Yoneda, Tamotsu Kasai · Electronics and Communications in Japan (Part II Electronics) · 1989
Abstract The Walsh transformation is a useful method which can replace the Fourier transformation for analysis of alternating‐numbers, and is suitable for digital waveform analyses. Since this is a binary transformation, its hardware realization is achieved easily. Using this advantage, this paper proposes a discrete Walsh‐transformation circuit using a switched‐capacitor circuit. This paper also proposes a solution of a problem of the change of power spectrum due to the phase‐shift of the input signal which prevents practical applications of the Walsh transformation to an electronic circuit. In the proposed circuit, a Walsh‐function wave based on a rectangular waveform synchronized with the input signal is formed, and this is used for the clock of the switched‐capacitor discrete Walsh‐transformation circuit. This arrangement makes the signal‐detection period variable so that the signal is always processed with no phase shift. This arrangement itself is also suitable for a switched‐capacitor circuit. A prototype switched‐capacitor discrete Walsh‐transformation circuit (for 32 sampling points) was made with discrete components. The results confirm that the proposed method is effective for analyzing rectangular waves.