SU1425804A1 - Swinging-frequency oscillator - Google Patents

Description

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The invention relates to microwave radio technology and can be used in automated radio measuring apparatus for measuring the frequency characteristics of radio devices.

The aim of the invention is to increase the linearity of the frequency sweep, as well as expand the range of the output speed sweep speeds.

FIG. 1 shows the structural electric circuit of the generator of the swing frequency} in FIG. 2 and 3 are diagrams explaining the operation of the oscillating frequency generator.

i The oscillating frequency generator | (Fig. 1) contains a generator of 1 pulses, a binary counter 2, the first unit 3 of the BPP permanent memory, the first digital-analogue converter 4 (DAC) 4, the first amplifier 5 controlled by voltage generator (VCO) 6, one-shot 7, second permanent memory unit 8 (BPP), second digital-to-analog converter (DAC) 9, voltage accumulator 10, generator 11 of a triangular voltage, second amplifier, inverting amplifier (13. The generator P of a triangular type -; the receiver (Fig. 1) contains a digital-analog converter (DAC) 14 and the block 15 of the permanent memory (WFP).

The generator works as follows.

A generator of 1 clock pulses produces pulses (Fig. 2a, Za), which synchronize the operation of the oscillating frequency generator and the external indicating device. Binary counter 2 performs pulse counting. After passing 2 pulses, where m is the binary counter, a pulse triggers a one-shot 7. A negative pulse appears on the output of the transfer (Fig. 2b), which prohibits counting and is a return pulse, for synchronization of the external indicator device. After the end of the pulse, the score is again resolved. At the same time, at the outputs of the first BFB 3 and the second BFB, 8, codes are set in accordance with the tables previously entered in them. Impulses (Fig. 2c), arriving at the lower address input of the second BZP 8, also arrive at the input of the generator I. The generator 11 can be made in the form of an integrator, constant time

n c

0

Which is chosen to be approximately 10 TfT, where Trti is the pulse repetition period of the 1 clock pulse generator. This condition allows to obtain a good linearity of the triangular voltage at the output of the generator 11. Next, the pulses from the output of the generator 11 are fed to the inputs of the second amplifier 12 and the inverting amplifier 13. By adjusting the bias of the second amplifier 12 and the inverting amplifier 13, a single voltage is applied to them exits, for example positive. Thus, the inputs of the reference voltage of the first D / A converter 4 and the second D / A converter 9 are supplied with equal anti-phase amplitudes. direct voltages (Fig. 2g and d, respectively). At the output of the first DAC 4, the voltage of the sawtooth varies between adjacent sweep points (Fig. 2e), taking values at odd points in accordance with the code recorded in the first BFR 3. At even points at a zero voltage at the input of the reference voltage of the first DAC 4, a change in the code at the output of the first BUT 3 does not affect the output voltage of the first. DAC 4. At the output of the second DAC 9, the voltage also varies sawtooth between adjacent sweep points (Fig. 2g), taking values at even points in accordance with the code recorded in the second BFR 8. The code at the output of the second BS1 8 changes at odd points at zero voltage at the input of the reference voltage of the second DAC 9 does not affect the output voltage of the second DAC 9. The voltage at the output of the adder 10, the inputs of which receive the voltage from the first DAC 4 and the second DAC 9 is equal to their sum (Fig. 2h), i.e. represents a piecewise linear approximation between 2 points. The voltage from the output of the adder 10 is fed to the input of the first amplifier 5 and further to the input of the VCO 6, the frequency at the output of which (Fig. 2i) is a partial linear-linear approximation between 2 points.

The accuracy of the approximation of the frequency characteristics of the VCO 6 is determined by the linearity and stability of the control voltages at the inputs of the reference voltage of the first DAC 4 and the second DAC 9, therefore, the generator 11, as well as the second nipple 12 and inverting

amplifier 13 must be powered by stabilized voltage sources. In order to expand the swing speed range of the output frequency of the oscillating frequency generator, it is preferable to perform the generator 11 in the form of serially connected BS 15 and CDL 14. PPF 15 is used to store the values of the binary code of the argument function of the triangle type. Thus, at the output of the DAC 1A, there is a step triangular voltage (FIG. 35, curve 1), Second amplifier 12 and an non-inverter counter, second high-voltage converter and voltage adder, the other input of which is connected to the output of the first digital-analog converter, connected in series a triangular voltage generator, the input of which is connected to the lower address input of the second constant memory unit, and a second amplifier, as well as an inverting amplifier, the outputs of the second amplifier and inverting amplifier with connected to the input

taty amplifier 13 at large scopes of the reference voltage of the first and

height x swing can somewhat integrate the step voltage (fig, 3b, curve 2). Their speed is chosen so that they do not distort the triangular voltage at maximum sweep speeds.

Claims (1)

Invention Formula 1, A oscillating frequency generator containing a serially connected binary counter, a first block of on-board memory and a first digital-analog converter, a first amplifier connected in series and a voltage-controlled oscillator, as well as a clock pulse generator increase, frequency swing linearity, one-shot inserted, the input of which is connected to the transfer output a binary counter, serially connected to the second block of permanent memory, the address inputs of which are connected to the correspondent | singing outputs the second digital-to-analog converters, the input of the inverter of the skinny amplifier is combined with the input of the second amplifier, the output of the clock pulse generator connected to the input of the binary counter, the output of the voltage adder is connected to the input of the first amplifier, the output of the single-oscillator is connected to the reset input of the binary counter. 2, The generator according to claim 1, t, l, and - due to the fact that, in order to expand the range of output speeds, the triangular voltage generator is designed as series-connected constant-memory unit and a digital-to-analog converter, the output of which is the output of a triangular voltage generator, the input of the higher address the discharge of the constant memory block is input by the i-generator of a triangular voltage, and the inputs of the lower address bits of the fixed memory block are connected with the corresponding outputs The best bits in the binary counter. llMIMIIIIriiillllllillllllL, O i G 6