Digital microwave receiver technology

Abstract

This paper reports the impact of digital signal processing on microwave receiver technology. The majority of modern receiver designs are based on digital technology. Wideand narrow-band receivers will be presented. The wide-band receivers cover approximately 1-GHz instantaneous bandwidth and are used to intercept radar pulses. Current narrow-band receivers cover up to 50-MHz instantaneous bandwidth and are primarily used for receiving communication signals. Two approaches for wide-band receiver design will be discussed. One is the conventional digital receiver. The other one is called the monobit receiver, which has slightly inferior performance in some respects, but can be built on a single chip. Narrow-band receivers are best implemented in software because they can more adapt to changes. Two types of receivers will be discussed. One is the software global positioning system receiver. The other one is called a transform-domain communication system. The object of this system is to avoid interference in a hostile communication environment.

An improved transient-type ice-penetrating radar

“…Though some commercial systems such as those of Geophysical Survey Systems Inc. (GSSI) and Sensors and Software have the advantage of accuracy and sampling rate, they use an analog sampling gate to convert signals to audio range. This process may lose some information (Tsui and Stephens, 2002). Compared with these commercial systems, our system has no analog sampling gate or analog-to-digital conversion, and integrates the analog-to-digital circuit and the control circuit together to form a cohesive whole.…”

Design and performance evaluation of a digital wideband receiver on a hybrid computing platform

“…The input RF signal is down converted into intermediate frequency (IF) and digitized using a high-speed analog to digital converter (ADC). This process retains all information and the digital receiver produces an overall better performance than the analog counterpart [1].…”

Implementing FFT-based digital channelized receivers on FPGA platforms

“…As a consequence, there appear big discrepancies between the calculated P f a and the theoretical one deduced for continous gaussian noise samples. 5 It can be observed that the calculated curve has steps due to the fact that both the real and the imaginary parts of the output are integers, so that the module range is not continuous. …”

“…Figure 19 shows the difference between the theoretical and the calculated P f a curves when σ = 256. 5 For lower values of σ, the butterfly truncation modifies the probability density functions of the noise samples. As a consequence, there appear big discrepancies between the calculated P f a and the theoretical one deduced for continous gaussian noise samples.…”

“…A classical receiver which accomplishes these requirements is a channelized receiver [3] which separates signals according to their frequencies. Recent advancements in Analog-to-Digital Converters (ADC) technology and in the speed of digital processors have made it possible to design relatively wide band digital channelized receivers [4][5][6][7]. The use of digital channelization in comparison with the analog approach allows to improve the imbalance between filters, which is one of the fundamental problems in analog receivers (digital circuitry is inherently reproducible, reliable, and accurate).…”