Digital radio receivers and problems of analog-to-digital conversion of narrow-band signals
Abstract
Four methods of analog-to-digital conversion in digital radio receivers are described, considering that an additive mixture of signal and interference at the input of such a receiver is usually a narrow-band process. All four methods utilize the quasi-harmonic form of narrow-band oscillations. The first method is based on resolving the input process into two components in quadrature. The second method is based on representing the input process as a set of envelope reading and phase reading pairs, readings taken at a discretization frequency determined by the width of the signal spectrum and taken at low oscillation levels. The third method is based on sampling (strobing) over a time interval which, while only a fraction of 1/f sub 0 (f sub 0 = center frequency of the input signal), can be made sufficiently long to reduce integrator and memory requirements. The fourth method is based on quantization with prediction and use of redundancy for widening the dynamic range of the digital channel in the receiver. The applicability of each method is determined by its systematic error, analysis and calculation of which indicate the limitations of each method.
- Publication:
-
USSR Rept Electron Elec Eng JPRS UEE
- Pub Date:
- August 1984
- Bibcode:
- 1984RpEEE....R..20P
- Keywords:
-
- Analog To Digital Converters;
- Digital Systems;
- Narrowband;
- Radio Receivers;
- Signal Processing;
- Errors;
- Radio Frequency Interference;
- Communications and Radar