SU746480A1 - Digital generator of modulating signal - Google Patents

Description

(54) DIGITAL GENERATOR MODULATING SIGNAL

one

The invention relates to the field of radio communication, can be used to obtain a modulating signal from the original binary signal for systems of transmitting discrete information with a limited project.

A device l is known, which contains a time interval converter in a sequence of pulses, a unit of weighting coefficients, an output reversible counter-register, a unit for decoding linear approximation sections, a block of memory. The use of multiply and divide operations in a known function generator limits its speed.

It is also known a device 2 containing elements AND, a pulse generator / counter, an OR element, a fixed frequency generator 20 consisting of a pulse generator and a frequency divider, a ring shift register, an argument counter, the counter input connected to the output of the OR element connected the inputs with the outputs of the elements And, the first inputs of which are connected to the output of the generator of fixed frequencies and the second inputs are connected to the single outputs of the ring register shift-go

hectare, the argument counter is connected by a counting input to the output of a generator of fixed frequencies, and the bit inputs are connected to the zero outputs of the annular shift register, the clock input of which is connected to the output of the argument counter.

The known device has limited functionality since it cannot synchronize from an external signal. The presence of a frequency divider involves the operation of a generator with a fixed grid; frequencies, which limits the accuracy of reproduced functions, and the relative complexity of control limits its speed.

The aim of the invention is to increase speed and enhance functionality by applying synchronization with an external signal to form the moment of manipulation according to the required law.

Claims (2)

The goal is achieved by introducing the element NOT, the decoder and the digital-analog converter into the device containing the elements AND, the pulse generator and the counter, the output of the pulse generator 15a connected to the first inputs of the first and second elements AND, the second inputs of which are connected to the input of the device and the output of the NAND element, and the third inputs are nth (nk6 number of approximation stages) and the first outputs of the scrambler, respectively, the outputs of the first and second elements And are connected to the summing and The reading inputs of the counter, the outputs of which are connected to the outputs of the decoder, the outputs of which are connected to the corresponding inputs of the digital-analogue TOffbfo converter, the input of the element are NOT connected to the input of the device, the output of the device is the output of the analogue analogue a. tel. The drawing shows the proposed generator. The generator contains the element NOT 1 elements AND 2 - 3, the counter 4, the decoder 5, the digital-analog converter 6, the generator of 7 pulses. The generator of the modulating signal operates as follows. A binary digital signal is fed to the information input of the device, which carries information, and the output of the output of the pulse generator is followed by clock pulses with a period of no more than Chem | to the duration of the shortest data pulse (where is the number of counter bits 4) If.in the first moment after switching on the counter 4, it is in the intermediate (not extreme) state, then from the output of the decoder the minimum code combination Qmiri and the maximum 0 "dL one. analog converter n-a t, the network inputs of the elements And 2 and 3 effects Admissible, logical. that at the moment of switching on the information input of the device into the operation logically, then the tact impulses come to the input of the addition of the counter 4 through the first element AND 2. As clock pulses arrive at counter 4, various code patterns affect the inputs of decoder 5. These code combinations are decrypted by the decoder 5 and fed to the inputs of the digital-to-analog converter B. Moreover, each code combination at the input of the 5 C decoder corresponds to a low potential (logical O) only at one of its n outputs. Digital-to-analog preobraerva .tel b assigns the KAAD dZhiyf13ooShnoy od6voY T om bination of a given functional zyvyoymdstyopredelenny ypoieffe Sn p and its output voltage completely fill counter 4 sitnal on vyhd Q decoder 5 is replaced with a logical O, the output logic Qmin axes taets H., in the haHe rezhu what .. about. Both elements are closed, the clock pulses on the 1 meter 4 do not arrive. A high output voltage is detected by the VGA output to the analog transducer. The stable state of the chesh remains until the logical information O of the device is replaced with the information input. In this case, the first element 2 remains in the closed state, and at the first input of the second element I 3 after inversion by the element AND – NE 1 the logical O is replaced with logical, the second IZ element opens. The clock pulses, the passage through it, affect the subtraction input of counter 4, and at the output of the code-analog converter a transition from a high level of voltage to low is formed. The formation stops at the output (C, decoder 5 of logic O as a result of which the second element I 3 closes and a low voltage level is fixed at the output of decoder 5. This steady state remains until the logical information device is replaced with a logical one and then The process of forming a signal is repeated in reverse order. The use of a modulating signal generator; ala1 allows for a significant narrowing of the spectrum of the emitted signal, which is very useful in solving problems associated with the electromagnet Compatibility or when using a communication channel with a limited band. Invention A digital modulating signal generator comprising an AND element, a pulse generator and a counter, characterized in that, in order to improve speed and functionality, due to synchronization by an external signal of moment formation manipulation according to the required law, the element is NOT, the decoder and the digital-analog converter, and the output of the pulse generator is connected to the first outputs of the first and the second elements And, the second inputs of which are connected respectively to the input of the device and the output of the element. NOT, and the third inputs from the n-th (n-number of approximation sections) and the first outputs of the decoder, respectively, the outputs of the first and second elements And connected respectively summing and subtracting inputs of the counter, the outputs of which are connected to the inputs of the decoder, the outputs of which are connected to the corresponding inputs of the digital-analog converter, the INPUT of the element is NOT connected to the input of the device, the output of the digital-analog the converter is the output of the device. Sources of information taken into account in the examination USSR certificate About F 1/02, 1975. USSR certificate 06 F 1/02, 1975 (about