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Phase discriminator on logical gates

Phase modulated signal can be described by a formula:  . A signal changed by the low of phase corner modulation . Selection of the modulated signal from the sum of two signals is carried out on nonlinear quadratic multiplier. On his output the signals are proportional to the value: . The second element is a signal with the frequency , repressed by the filter of lower frequencies, and the first element is a signal changed by the low of phase modulation. k – multiplier proportionality factor. For the small corners . A signal after a filter: .

For phase discriminators there are large requirements to stability of phase of exemplary generator. A low-frequency constituent is found in the bar of filter’s low frequencies. For impulsive signals ,  the amplitudes do not affect on the law of modulation, and impulses are folded from the set of harmonic constituents. Fig.1 the chart of phase discriminator on logical gates. U1, U2 – frequency dividers with relative pulse duration 2, U3 – eliminating OR, U4 – filter of lower frequencies. It is necessary to take into account for a circuit, that the value of phase to the maximal level changes for two period of input signal (fig.2).

Fig. 1. Chart of phase discriminator on logical gates.

Fig. 2. Time diagram of phase discriminator.

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