SU1223393A1 - Demodulator of frequency-shift keyed signals - Google Patents

Abstract

The invention relates to communication technology and may be. used in data transmission equipment. The purpose of the invention is to reduce edge distortion of signals with increasing transmission speed. The device contains a pulse former 1, a measuring counter 2, a code converter 3, a key 4, 1st and 2nd dividers 5, 6 frequencies, a phase detector 7, an low pass filter 8, a threshold unit 9. The reduction of the edge distortion of the signals is achieved by introducing a key, a code converter and measuring counter. 1 il. § (/) -)

Description

The invention relates to communication technology and can be used in data transmission equipment.

The purpose of the invention is to reduce edge distortion of signals with increasing transmission speed.

The drawing shows a structural electrical circuit of the proposed demodulator.

The frequency-manipulated demodulator contains a shaper 1 pulses, a measuring counter 2, a code converter 3, a key 4, the first 5 and second 6 frequency dividers, a phase detector 7, a low-pass filter 8, a threshold unit 9.

The demodulator works as follows.

. The frequency-manipulated (FM) signal received from the communication channel is fed to the input of the transmitter 1 pulses, generated by only short pulses at the time of the transition of the FM signal through the zero level

The pulses from the output of the pulse shaping device 1 are fed to the control input of the installation to the zero state of the measuring counter 2, and the pulses of the reference frequency F. received to its (counting) reference input increase its state.

Thus, at the moments of the transition of the FM signal through the zero level, the state of the measuring counter 2 characterizes the duration of the past period of the FM signal in the frequency cycles of the reference frequency F (j.

The code converter 3 connected to the outputs of the measuring counter 2 converts the state of the latter into the corresponding code, which, under the influence of the pulse from the output of the pulse generator 1, via the public key 4 is written to the first binary frequency divider 5, the second frequency divider 6 is thus set to zero state the After

1223393

This is both divider 5 and 6 frequencies under the influence of high reference frequency

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thirty

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Fg arriving at their (counting) reference inputs work synchronously until the next pulse arrives from the output of the driver 1 pulses.

The output oscillations of the binary dividers 5 and 6 of the frequency are converted by the phase detector 7 into pulses of corresponding duration. The constant component of the pulse sequence is extracted by the lowpass filter 8. The threshold unit 9 regenerates the transmitted information in accordance with the value of the constant component.

Claims (1)

Invention Formula A demodulator of frequency-manipulated signals containing a pulse shaper, the output of which. connected to the control inputs of the first and second frequency dividers, the outputs of which are connected to the corresponding phase inputs of the phase detector, the output of which is connected through the low-pass filter to the input of the threshold unit, while the input of the pulse shaper is the signal input of the demodulator whose reference input are the reference inputs of the first and second frequency dividers, characterized in that, in order to reduce the marginal distortion of the signals when the transmission rate is increased, a key, a code converter, and measurements are entered into it - a heating meter, the outputs of which through a code converter are connected to the signal inputs of the key, the outputs of which are connected to the signal inputs of the first frequency divider, the control input of which is connected to the control inputs of the key and the measuring counter, the reference input of which is connected to the reference input of the first frequency divider. Editor N. Dankulich Compiled by O. Geller Tehred I.Popovich Proofreader L. Pilipenko 1726/60 Circulation 624 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Branch PPP Patent, Uzhgorod, st. Project, 4 five 0 five 0 five 0 five Fg arriving at their (counting) reference inputs work synchronously until the next pulse arrives from the output of the driver 1 pulses. The output oscillations of the binary dividers 5 and 6 of the frequency are converted by the phase detector 7 into pulses of corresponding duration. The constant component of the pulse sequence is extracted by the lowpass filter 8. The threshold unit 9 regenerates the transmitted information in accordance with the value of the constant component. Invention Formula A demodulator of frequency-manipulated signals containing a pulse shaper, the output of which. connected to the control inputs of the first and second frequency dividers, the outputs of which are connected to the corresponding phase inputs of the phase detector, the output of which is connected through the low-pass filter to the input of the threshold unit, while the input of the pulse shaper is the signal input of the demodulator whose reference input are the reference inputs of the first and second frequency dividers, characterized in that, in order to reduce the marginal distortion of the signals when the transmission rate is increased, a key, a code converter and measure - a heating meter, the outputs of which through a code converter are connected to the signal inputs of the key, the outputs of which are connected to the signal inputs of the first frequency divider, the control input of which is connected to the control inputs of the key and the measuring counter, the reference input of which is connected to the reference input of the first frequency divider.