SU485570A1 - Frequency modulator - Google Patents

Description

 The invention relates to modulators and can be used in telegraphy for the transmission of discrete information over communication channels. The known frequency modulator, which contains at least two master oscillators, the outputs of which through a controlled switching circuit are connected to the input of the N-bit frequency divider, and the output filter has a large number of harmonics in the spectrum of the frequency-modulated signal. , The proposed device introduced shapers of stepwise nakedness and stepwise decreasing voltages, one named signal inputs of which are combined and connected to the corresponding unit outputs (N - 2) of the frequency divider bits, single outputs (N-1) and bits of which connected to the control inputs of the shaper of stepwise increasing voltage and, respectively, to the second and first inputs of the implicator, whose output is connected to the control input of the shaper of stepwise decreasing voltage, and these Qormi; s rovateley combined and connected to the; filter input. The step-down and step-increasing voltage shaper units are made in the form of (N -2) {parallel branches, each of which consists of JK / IH-HE series-connected iK circuits and a weight resistor, and to form a step-down voltage K 2 dL | shaper incrementally {voltage. The drawing shows a block diagram of the proposed frequency modulator. f Modul5grr contains the master oscillators (tori 1 and n 2, the outputs of which through a controlled switching circuit 3 are connected to the input of the L –discharge frequency divider 4, the shaper 5 speed increments | speed and the shaper 6 speed | descending voltage, the same signal | signals the inputs of which are combined and connected to the corresponding single outputs {- 2) of the bits of frequency divider 4, the single outputs (- 1) and N bits of which are connected to the control inputs of the former 5 speed-increasing voltage and respectively toromu imshiisatora and a first input 7, the output of which is connected to the control input of the 6 stepwise decreasing voltage, the outputs of formers 5 and 6 are combined and connected to an input filter 8.

The device works in the following way.

The drivers of generator 1 and 2 when applying to the information input of a controlled switching circuit 3 information symbols in the form O and are connected to the input of a p-bit frequency divider 4. A periodic sequence of pulses from generators 1 and 2 acts on this frequency divider 4, triggers 1G |,.,. (The 1T of which changes its state. The signals from the unit arms of the THG triggers affect the signal inputs of the formers 5 and 6, and the signals from the unit arms of the flip-flops and Tf - on the control inputs.

As a result, at the output of the imaging unit 5, a gradually increasing portion and the upper base of the trapezoidal signal are created, and at the output of the imaging unit 6, a stepwise killing step; section of this signal. When the output voltages of the formers 5 and 6 are added in time, a frequency-modulated trapezoidal signal is formed at the output of the frequency modulator, the spectrum of which is minimal. the number of higher harmonics. The components of the third, fifth, and seventh harmonics are additionally attenuated by the filter 8 formed by a capacitor connected to the output of the modulator in combination with the weight resistors of the drivers 5 and 6.

Subject invention

1. A frequency modulator containing 0 as far as two master oscillators, the outputs of which through a controlled switching circuit are connected to the input of the H-discharge frequency divider, and an output filter that differs 15 | With what to reduce Enhanced in the frequency spectrum. but the modulated signal, - entered form; Mirrorvatels of stepwise increasing and stepwise decreasing voltages, one20 Named signal inputs - which are combined and connected to the corresponding

s to soo

(N single outputs (f. - 2) of the bits of the frequency divider, single outputs (ff -1) and N bits of which are connected to the control inputs of the stepwise increment generator and respectively to the second and first inputs of the implicator , the output of which is connected to the control input of the fi-miroviator of a 30-step decreasing voltage, and the outputs of these drivers are combined and connected to the input of the filter.

2. The modulator according to Claim 1, of tl and h a yu and c, in that the formers of stationary 86, foam-decreasing and step-increasing stresses are made in the form of W-2) parallel branches, each of which consists of series-connected K circuits. OR-NOT and the weight resistor, moreover, for a stepwise decreasing voltage generator and /. To a 2-for a cTyneji4aTO voltage ramping device.