Direct bandpass sampling of multiple distinct RF signals

Abstract

Abstract-A goal in the software radio design philosophy is to place the analog-to-digital converter as near the antenna as possible. This objective has been demonstrated for the case of a single input signal. Bandpass sampling has been applied to downconvert, or intentionally alias, the information bandwidth of a radio frequency (RF) signal to a desired intermediate frequency.The design of the software radio becomes more interesting when two or more distinct signals are received. The traditional approach for multiple signals would be to bandpass sample a continuous span of spectrum containing all the desired signals. The disadvantage with this approach is that the sampling rate and associated discrete processing rate are based on the span of spectrum as opposed to the information bandwidths of the signals of interest.Proposed here is a technique to determine the absolute minimum sampling frequency for direct digitization of multiple, nonadjacent, frequency bands. The entire process is based on the calculation of a single parameter-the sampling frequency. The result is a simple, yet elegant, front-end design for the reception and bandpass sampling of multiple RF signals. Experimental results using RF transmissions from the U.S. Global Positioning System-Standard Position Service (GPS-SPS) and the Russian Global Navigation Satellite System (GLONASS) are used to illustrate and verify the theory.

A Pattern Construction Scheme for Neural Network-Based Cognitive Communication

“…PBCS requires a dynamic radio frequency (RF) Front-end because of dynamic spectrum utilization. This need was already handled when the studies of Akos et al [15] in which so-called Direct RF Sampling was applied to the RF Front-end. Then, Psiaki et al [16] have presented a new algorithm that finds the minimum sampling frequency and thus avoids overlap.…”

Direct radio frequency sampling methodology for multiple signals in an energy-sparse spectrum

“…In the case of multiple bands being present in the spectrum of interest, [7] describes a relation between sampling frequency f s and aliased frequency f a to avert the aliased bands from overlapping with zero and the Nyquist frequency f s /2. This relation is limited to 2 input signals only, and no algorithm is given which is applicable to N > 2.…”

“…This relation is limited to 2 input signals only, and no algorithm is given which is applicable to N > 2. Two basic constraints described by [7] are given as…”

“…Analytical methods exist that permit minimum bandpass sampling frequencies to be computed in the case of a single-band spectrum [1][2][3]. However, BPS has its issues for multiband signal spectrum due to certain constraints like aliasing, spectral folding, and reconstruction of information band [4][5][6][7]. In addition, there are no analogous equation sets available for a general multiband bandpass system consisting of signals with arbitrary center frequencies and bandwidths.…”

An efficient algorithm for bandpass sampling of multiple RF signals

“…A basic principle for downconversion of multiple radio frequency (RF) signals using the bandpass sampling has been introduced in [2]. In [3], they have described schemes to determine valid bandpass sampling frequencies for two distinct RF signals.…”