| 摘要 |
<p>ENHANCED DELTA MODULATION ENCODER An improved analog-to-digital encoder comprising an enhanced delta modulation encoder, The enhanced delta modulation encoder includes a spectrum tilter, a 1 bit analog-to-digital converter, a sampling circuit and an internal decoder. An analog input signal and an internal analog signal from the internal decoder are summed to provide an analog dither signal. The analog dither signal is tilted by the spectrum tilter and is provided to the 1 bit analog-to-digital converter which generates a digital signal. The sampling circuit receives the digital signal from the analog-to digital converter and generates a digital output which is fed hack to the internal decoder. The spectrum tilter comprises at least three integrator circuits and a clipping circuit connected in parallel to two of the three integrator circuits. The three integrator circuits tilt the frequency spectrum of noise above the maximum frequency of interest, and the clipping circuit prevents the encoder from becoming unstable.</p> |
