a modulation index
a parasitic amplitude modulation
synthesis of radio circuits
Phase modulation has gained the restricted extending because of complexity of formation of a signal with the big modulation index and presence of a parasitic amplitude modulation. Two ways of formation signals modulated on a phase are known: by retiming of the oscillatory circuit of the tuned amplifier and by vector addition it is peak – the modulated signals out of phase on 900. Both methods lead to presence of a parasitic amplitude modulation and insufficient magnitude of a modulation index <0.8, that demands application of frequency multipliers. The work purpose is working out of a principle of construction and circuit implementation of phase modulators with the raised modulation index without a parasitic amplitude modulation.
The way of formation of signals is developed for object in view achievement with phase modulation on the basis of use of active phase devices. The way is developed in an assay value of topology of radio chains in active basis and their reduction to an aspect of phase chains. On the basis of the developed way circuit implementation and ARC-basis is offered. Implementation is gained by comparison of a circuit transfer function and theoretical a transfer function of a phase chain.
The developed way has allowed to increase twice a modulation index in relation to known solutions, thus irregularity of a modulation characteristic has made less than 50, and depth of a parasitic amplitude modulation is equal to null. At a series connection of two such devices it is possible to increase an index of phase modulation to without a parasitic amplitude modulation.