| 摘要 |
PURPOSE:To improve both the converging performance and the accuracy of error detection control by monitoring the levels of discrimination and error signals and changing the time constant of an integrator based on the information on said monitoring. CONSTITUTION:An input 16-QAM signal 40 is transmitted through orthogonal phase wave detectors 41 and 41'. Thus the base bands of in-phase and orthogonal components are obtained and discriminated by A/D converters 43 and 43' after they passed through higher harmonic suppressor filters 42 and 42'. These in-phase and orthogonal components are supplied to D/A converters 51 and 52 by paths 3 and 4 as well as 3 and 5 through exclusive OR circuits 46, 47, 49 and 50 respectively. The outputs of both converters are added and vary the time constant of an integrator 53. In this respect, the capacity of the integrator 53 is controlled. The error is maximum with the step-out and therefore the capacity of the integrator 53 is reduced to decrease the time constant. This improves the converging performance. When the error degree is small, the capacity of the integrator 53 is increased to increase the time constant. Thus the control accuracy is improved. The correlation is secured between the polarity of the discrimination signal of the in-phase component and that of the error signal of the orthogonal component by means of exclusive ORs 45 and 48. |
