In mobile TV reception, fluttering ghost images are considered to be the severest picture impairments in view of visual quality. Fluttering ghost is caused by timing variation of TV horizontal synchronizing pulse due to frequency selective fading in multipath propagation. So that, It can be detected by measuring the dynamic variation of TV horizontal synchronizing pulse timing. This paper describes the method of measuring timing fluctuation while running on an urban street by use of a Rubidium oscillator as time standard with high stability. The spatial amplitude spectrum of timing fluctuation is analysed, and may be used to evaluate the picture quality in mobile TV reception.
Equipment, called as Es Interference Canceller, which compensates the TV picture impaired by Es interference waves due to the reflection by sporadic-E ionospere, is developed for TV relay stations. Experiment and theoretical analysis are made and more than 40 dB interference wave suppression is achieved. When the interference wave is a sigle, the picture is almost perfectly compensated. Even when multiple waves, more than 1 grade improvement is attained.
Error-correction for impulsive noise on teletext is very important, because it is impossible to correct bit-errors by waveform equalizers and ghost cancellers. The (272,190) code (1) has been derived from analyses of error-data collected in field tests. With this code a teletext service became possible even under the bit-error rate of 10^<-2>.
We have been proposed a new measurement method of effective radiated power using in-phase synthetic method, which is practicable even in a small test site. In this measurement, amplitude and phase data of the radiated field are successively measured with the scanning of the receiving antenna. In this paper, new scanning way of the receiving antenna is proposed and experimental results are presented to show the varidity of this method.
Most electric machines have winding coils and are connected to power supply lines. These coils and lines are distributed constant circuits which have many series and parallel circuits composed of L.C.R. If on or off the L C R circuit, it will be induced damped oscillation in them due to transient phenomena. This is the noise of electric machine. The damped oscillation can be calculated from the frequency-impedance characteristics of machines and their wave forms can be observed by oscilloscope of switching the circuit.
This paper reports on the dielectric constant and the outline of the profiles of layers within a snowpack which were measured continuously and automatically, using a new measurement system which consists of a parallel transmission line inserted into a snowpack, a time domain reflectometer (TDR), an A/D converter, a digital output port and a GP-IB controller.
The pupae of Drosophila virilis are expoused to DC high voltage E-fields (from 15 to 180 minute duration). The E-fields on the surface of a pupa is numerically calculated. The E-fields is enhanced at the back of the pupa's body and it reaches up to about 22 times of the uniform E-field at the feeler. The rate of emergence which emerged from expoused pupae is given for each tests. The emerged flies from expoused pupae mated-with each other, and mated with untreated flies. The obtained results showed, increased incidence of abnormal development occurred due to exposure.