A 4/15 code and a 4/11 code have been developed in the magneto-optical disc system with sample servo mechanism. We propose the application of PR systems, instead of differentail detection method. We also adopt Viterbi detection method with PR systems as PRML methods. Furthermore, another signal detection method making use of the unique property of the coding rule on 4/15 is proposed in this paper. Bit error rates of our systems are examined by computer simulation and compared with the conventional differential detection. The results show that our proposed systems exhibits excellent performance compared with the conventional one.

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In this paper, we have tried to applied several PRML(Partial Response Maximum Likelihood) methods to a 3B-2T code and a 4B-3T code, those of conventional ternary recording codes, and evaluated the performance of bit error-rate for necessary SNR at the reading point by using both techniques on state transition matrix and symbol transition matrix. The results show that PR(1,0,-1)ML method can be made the best performance among several combination of PRML method with a 3B-2T code and a 4B-3T code.

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In this paper, we make clear the properties of thirty FM Family codes through the analysis on coding rules. Then the combination of these codes with several PRML methods is investigated with bit error rate by computer simulation. The results show that nine FM Family codes can be performed better SN ratio than conventional FM code at error rate 10^<-4>.

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In the integrated detection for M^2 code known as an excellent DC free code, the compensation method for the degradation of eye diagram due to bandwidth limitation to suppress the noise component at high frequency by controlling the transition point of recording waveform is proposed. Eye opening, timing margin and bit, error rate are obtained by computer simulation. It is clarified that we can improve the error rate performance by our compensation method.

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The influence of the correlation coefficients of colored noise on the error rate performance of PRML system is studied. For two partial response systems, PR(1,1,-1,-1) and PR(1,1,0,-1,-1) systems, the upper bounds on error rates are derived and expressed as a function of the correlation coefficients of noise sequnces at the input of Viterbi decoder. The theoretical value of error Fate is also compared with the simulated and the result shows that there is close agreement between them. Furthermore, the relationship between the correlation coefficient of colored noise and the error rate performance is clarified.

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The performance of bit-by-bit decoding and PRML system for various partial response (PR) systems with the transfer function (1 + D^l)^n(1 - D^m) is studied. First, the required SNR's at the discrimination point to achieve the error rate of 10^<-4> are obtained and compared. Then, the error rates of PRML systems which are the PR(1,1,-1,-1) and PR(1,1,0,-1,-1) systems combined with Viterbi decoding are obtained. The results show that for bit-by-bit decoding PR(1,1,0,-1,-1) system gives the best performance among these PR systems and for PRML system the same PR system exhibits better performance compared with PR(1,1,-1,-1) system.

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The error rate performance of PRML system in perpendicular magnetic recording by a multi-layered main-pole head is studied. First, the SNR at the discrimination point and bit-error rates of bit-by-bit decoding are obtained for several partial response (PR) systems by taking the increase of noise due to equalization into consideration. Then, bit-error rates of PRML systems for these PR systems are obtained and compared with that for a conventional PR system. The results show that among these PR systems PR(1,0,0,0,-1) system shows the best performance and improves the SNR by about 1.9 dB for bit-by-bit decoding and by about 4.1 dB for PRML systems at the error rate of 10^<-4> compared with the conventional PR system.

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In recent years transmission of news program from local news departments, branch office, news car and urgent reports car(SS-1) is inclined to increase, then quick receiving of it is indispensable. But it is time-consuming to control Telecon terminal in use at local news departments and branch office because operators must telephon to that terminal for remort control each time. Becides remort control of FPU(Field Picture Unit) receiving base is aiso manual. In the present condition we cannot deal with receoving system quickly. Then this paper discribes the device to control Telecon and FPU totally with easy operation using a personal computer(PC-9801).

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