Digital modulation plays a significant role in efficient wireless communication. It allows the transmission of digital data via air on high frequency carrier waves. The worst case communication channel is usually in the urban environment where there are many obstacles. Due to the obstacles and reflectors, the transmitted signal arrives at the receiver from various directions over a multiplicity...

With increased saturation of the VHF band II used for FM, few frequencies are available for new radio stations in many markets. This paper describes the benefits of using the In Band On Channel (IBOC) signal in an all-digital configuration to boost the number of effective audio services in the FM band. A new method of creating an all-digital IBOC signal configuration is described. Multiple inst...

LOFAR (the Low Frequency Array), a distributed digital radio telescope with stations in the Netherlands, Germany, France, Sweden, and the United Kingdom, is designed to enable full-sky monitoring of transient radio sources. These capabilities are ideal for the detection of broadband radio pulses generated in cosmic ray air showers. The core of LOFAR consists of 24 stations within 4 square kilom...

A terahertz-wave communication system directly connected to an optical fiber network is promising for application to future mobile backhaul and fronthaul links. The possible broad bandwidth in the terahertz band is useful for high-speed signal transmission as well as radio-space encapsulation to the high-frequency carrier. In both cases, the low-latency feature becomes important to enhance the ...

Personal Communications Services (PCS) require low-power radio technologies. One such transceiver architecture employing frequency-hopped spread-spectrum techniques is presented. System features such as antenna diversity with equal-gain combining and sequential hop combining are incorporated into the transceiver design to achieve robust wireless digital data transmission over fading channels. A...

This paper describes and discusses the results of tests carried out on two families of PDM (Pulse Duration Modulation) AM transmitters. A variety of tests have been done using two tone techniques to evaluate the transmitters for linearity. Testing was carried out both into a 50 ohm resistive load and into a bandpass load to simulate the effects of a limited bandwidth antenna as proposed by USA ...

The wireless market is developing very fast today with a steadily increasing number of users all around the world. An increasing number of users and the constant need for higher and higher data rates have led to an increasing number of emerging wireless communication standards. As a result there is a huge demand for flexible and low-cost radio architectures for portable applications. Moving tow...