Design And Simulation Of The New Method Of Impulse Ladder Modulation

This paper presents the algorithms of digital control system of impulseladder modulator of shortwave transmitter, in which both the arithmetic designand the simulation results are included.Nowadays, mass radios in domestic adopt control system of PSM (PulseStep Modulation) modulator. However, they are realized in simulation almost.Many processes are realized in hardware circuit. The fimction of system isrestricted due to guideline of parts of an apparatus is simulative. On the otherhand, control system of modulator is not able to detect when it run. Thus, whenfault appeared, high-voltage lose control of modulator and long-playingshutdown are inevitably. Digital rebuilding in originally system is urgentlyneeded for finding a control system that it has more steady, reliable andextensible. This paper discussed control system of PSM modulator whichadopted 32 bit float DSP and 24 bit A/D. The system has extraordinary processprecision. Soft arithmetic replaced hardware realizing make system moreminiature and flexible, moreover, upgrade become easier.This paper presents two new methods that they are improving equivalentarea and extending symmetry synchronization sampling. The method ofimproving equivalent area modified the station of PWM making them changealong with error of PSM. Thus it can restrain hypo-frequency better and make ,error of phase depress. The method of extending symmetry synchronizationsampling has more high-speed. It changed amount of PWM via altering samplefrequency which is changed getting across linearity interpolation. This methodmakes the compensation more consummate and the wave of output perfect.Moreover, these are fit for realized by DSP. This paper made out analysis incomputer simulation to the new methods and approved their excellent capability.In addition, this paper put forward the design precept of measuringfrequency circuit and switch module circle on-off. Then this digital controlsystem is more consummate and can monitor status of running and eliminatemalfunction automatically making broadcast continuously is possible.