Alias-free digital click modulator

STEFANAZZI, LEANDRO; OLIVA, ALEJANDRO RAUL; PAOLINI, EDUARDO

IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Lugar: New York; Año: 2013 vol. 9 p. 1074 - 1083

1551-3203

An alias-free, discrete-time click modulator is devel- oped in this paper. Previous approaches rely on translating the con- tinuous-time click modulator to a discrete-time setting, although a key component in the click modulator?the analytic exponential modulator-cannot be exactly transformed to the discrete domain. Every discrete-time version of the click modulator reported in the literature is prone to aliasing effects that are ameliorated, but not eliminated, using interpolation techniques. The precision of the switching times of the output square wave is critical to click modulation because uncertainties in their deter- mination adversely affect the performance and SNR of the modu- lator. A novel method that uses frequency domain information to compute these switching times without error is also presented. This two techniques are used to develop an off-line discrete-time click modulator that achieves a SNR larger than 180 dB for both multitonal and bandpass signals.