Title :
Two-frequency synthesizer with shaped quantization noise [for impedance bridges]
Author :
Small, G.W. ; Fiander, J.R.
Author_Institution :
Nat. Meas. Lab., CSIRO, Lindfield, NSW, Australia
Abstract :
Some impedance bridges require a signal source of accurately known frequency, and sinusoidal waveform of good spectral purity. These requirements are here met by combining the functions of synthesis and waveform generation to produce a signal that is free from phase modulation. Sidebands resulting from quantization errors are shaped to reduce those adjacent to the signal, at the expense of more remote sidebands where filtering is more effective.
Keywords :
bridge circuits; digital-analogue conversion; direct digital synthesis; electric impedance measurement; quantisation (signal); waveform generators; ADC; DAC; accurately known frequency; code generation algorithm; feedback gain; impedance bridges; look-up table; shaped quantization noise; shaped sidebands; signal source; sinusoidal waveform; spectral purity; stepped waveform; two-frequency synthesizer; waveform generation; Bridges; Filtering; Frequency; Impedance; Noise shaping; Phase modulation; Quantization; Signal generators; Signal synthesis; Synthesizers;
Conference_Titel :
Precision Electromagnetic Measurements Digest, 1998 Conference on
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-5018-9
DOI :
10.1109/CPEM.1998.700026
