DOI:10.1049/ree.1975.0051

出版商:IERE    

年代:1975

数据来源: IET

摘要:

Various design techniques are described for conventional equalizers that use transversal filters. Two different arrangements are studied. In the first, the equalization process is located at the receiver, and in the second it is shared between the transmitter and receiver. The optimum linear and non-linear equalizers, together with some suboptimum designs, are described for each of the two arrangements, and the tolerances of the different systems to additive white Gaussian noise are compared for different values of the sampled impulse-response of the channel.It is assumed that a serial digital baseband signal is transmitted over a linear baseband channel whose sampled impulse-response is known. The practical implementation of the filters and techniques for the automatic or adaptive adjustment of the equalizer tap gains are not considered. The aim of the paper is to clarify the basic principles of the various equalization processes studied and to demonstrate some of the interesting relationships that exist between the different equalizers.

DOI:10.1049/ree.1975.0052

出版商:IERE    

年代:1975

数据来源: IET

摘要:

A digital function generator has been designed and constructed based on the solution of the simple harmonic differential equation using rate multiplier techniques. The generator is capable of operating over eight decades of frequency 10−4≤f≤104Hz providing outputs of triangle, square or sinewaves. Quadrature outputs, starting and stopping at any point in the cycle, are possible with this oscillator.Extensive simulation studies have fully established the nature of the errors inherent in the performance of this circuit. Results on the practical performance of the generators are given in both time and frequency domains.

DOI:10.1049/ree.1975.0053

出版商:IERE    

年代:1975

数据来源: IET

摘要:

For the design of sharp-cut-off low-pass filters, derived from all-pole Chebyshev filters, one needs to determinen, the order of the filter;m, the order of finite zeros; ω0, the location of the zeros; and ε, the ripple controlling factor, from the required specifications of cut-off slope, tolerable pass-band deviation, minimum acceptable attenuation in the stop-band and any other desirable constraints. The information with regard to cut-off slope and partial results with regard to stop-band tolerance are already available; the present paper gives the other necessary details in respect of pass-band as well as stop-band performances. The pole positions are also tabulated for some low orders; permissible allowed values ofm; ω0ranging from 1.01 to 2.00; and one representative value of ε.

DOI:10.1049/ree.1975.0054

出版商:IERE    

年代:1975

数据来源: IET

摘要:

A radio-navigation relay system has been developed to monitor and track the position of remote objects such as ships, buoys and balloons. R.f. signals received from a chain of radio-navigation transmitters are converted to an audio frequency and limited in amplitude in a simple low-cost converter unit. The audio output, which retains the position information contained in the initial navigation signals, may be telemetered over conventional voice-frequency radio-telephone or land line networks to a receiver/decoder station.The design principles are described and the results of field trials presented together with proposals for further applications such as marine collision avoidance, pilotage and radio navigation chain stability monitoring.

DOI:10.1049/ree.1975.0055

出版商:IERE    

年代:1975

数据来源: IET

摘要:

This paper describes 150-MHz, 20-kW coaxial line pulse transmitters constructed for the study of radar aurora. Tuned quarter-wave lines have been used in the high power r.f. amplifier stages and a novel method has been developed to decouple the r.f. input and output feed points from the anode and grid d.c. supply voltages. A solid-state pulse modulator provides the anode and screen power to to the final stage r.f. amplifier. The transmitters have been operated successfully at remote, unattended field stations, where reliability, stability of the output pulse power and self-protection shut-down controls were important design criteria.

DOI:10.1049/ree.1975.0058

出版商:IERE    

年代:1975

数据来源: IET