Showing papers on "L band published in 1996"

GPS Multipath Fade Measurements to Determine L-Band Ground Reflectivity Properties

Abstract: In personal satellite communications, especially when the line-of-sight is clear, ground specular reflected signals along with direct signals are received by low gain, almost omni-directional subscriber antennas. A six-channel, C/A code processing, global positioning system (GPS) receiver with an almost omni-directional patch antenna was used to take measurements over three types of ground to characterize 1.575 GHz specular ground reflections and ground dielectric properties. Fade measurements were taken over grass, asphalt, and lake water surfaces by placing the antenna in a vertical position at a fixed height from the ground. Electrical characteristics (conductivity and dielectric constant) of these surfaces (grass, asphalt, lake water) were obtained by matching computer simulations to the experimental results.

2.6 GHz band satellite ISDB system for mobile reception

Abstract: At the World Administrative Radio Conference (WARC)-92, the 2.6 GHz frequency band was allocated to a group of East Asian countries including Japan. This band is being studied for use in mobile multimedia broadcasting. This paper describes the outline of a system for 2.6 GHz band mobile multimedia broadcasting services, together with its requirements. In particular, the effects of the broadcasting signals attenuation due to shadowing by buildings and foliage, and the signals deterioration due to multipath propagation and fading, must be taken into account in order to realize the 2.6 GHz band system. This study considers the economic and technical constraints related to the modulation schemes, transmitting power, satellite antenna reflector aperture, the gain of the receiving antennas and the scale of the satellites. The configuration of satellite hardware systems based on the channel plan, channel bandwidth, and other specifications is investigated taking into account of these constraints. For example, a bit-rate of 4.8 Mbps can be provided when a 2-ton class satellite bus is utilized. This indicates that 2.6 GHz band services are technically feasible.

L-band satellite receiver

Abstract: a L-band receiver antenna 10; a low-noise amplifier 20; first and second amplifier 30 and 31 for amplifying a signal passed through the low-noise amplifier 20; a band pass filter 40 for filtering the whole band of an input signal; a intermediate frequency section 500 for outputting an intermediate frequency by a single synthesizer 52; a costas loop section 700 including a temperature compensating voltage-controlled oscillator 100 for oscillating a reference frequency used in the single synthesizer 52, and a reset circuit 110 for setting an initial value to the temperature compensating voltage-controlled oscillator 100; and a sampling section 80 for sampling a demodulated data.