Title :
Increased information rate by oversampling
Author_Institution :
AT&T Bell Labs., Murray Hill, NJ, USA
fDate :
11/1/1993 12:00:00 AM
Abstract :
A noiseless ideal low-pass filter, followed by a limiter, is normally used as a binary data channel by sampling the output once per Nyquist interval. Detectors that sample more often encounter intersymbol interference, but can be used in ways that increase the information rate. A signaling system that achieves an information rate of 1.072 b/Nyquist interval by allowing the detector to sample at times a half Nyquist interval apart is presented. This rate increase is small, but it shows that, in principle, oversampling does permit faster rates. Another signaling system that more closely resembles a digital data system is also presented; it has rate 1.050. By allowing a more irregular pattern of sampling times, the rate is increased to 1.090 (or 1.062 for the `digital´ system)
Keywords :
digital communication systems; filtering and prediction theory; information theory; intersymbol interference; limiters; low-pass filters; telecommunication channels; telecommunication signalling; binary data channel; digital data system; information rate; intersymbol interference; limiter; noiseless ideal low-pass filter; oversampling; sampling times; signaling system; Communication system signaling; Data systems; Detectors; Digital systems; Information rates; Interference; Low pass filters; Measurement units; Sampling methods; Time measurement;
Journal_Title :
Information Theory, IEEE Transactions on