摘要:

By using computer control and correction, the noise parameters of an amplifying device can be obtained as an immediate display from system noise measurements without the need of having subsequently to make tedious calculations. The means of achieving this are described in the paper, together with results obtained by applying the facility to microwave amplifiers incorporating GaAs f.e.t.devices mounted in microstrip.

DOI:10.1049/ree.1982.0068

出版商:IERE    

年代:1982

数据来源: IET

摘要:

A test equipment for simulating the Rayleigh-distributed fading encountered in mobile radio is described. The fading is achieved by in-phase and quadrature modulation of the radio signal by two independent Gaussian noise signals. The noise formation and filtering are performed using a microprocessor for which the clock frequency can be varied to control the fade rate. The simulator has been designed to handle amplitude modulated signals and is being used in the development of s.s.b. mobile-radio receivers.

DOI:10.1049/ree.1982.0069

出版商:IERE    

年代:1982

数据来源: IET

摘要:

The operating principles of the Quate-Lemons scanning acoustic microscope and some recent developments in the detection and interpretation of acoustic images are reviewed. In particular the measurement of elastic constants using the microscope, which may ultimately provide a new high resolution technique for material characterization, is demonstrated.

DOI:10.1049/ree.1982.0070

出版商:IERE    

年代:1982

数据来源: IET