SU102981A1 - Apparatus for measuring group retardation time in the high-frequency path of radio-relay lines - Google Patents

Description

The invention relates to the field of measurements of the bulk time deceleration in the high-frequency path of radio relay lines.

The main disadvantages of devices known and used for such measurements, the action of which is based on the fact that the deceleration time is determined by the frequency of self-oscillations arising in the measuring value, covering the circuit under study, are not sufficiently high accuracy of the measurement results and the impossibility of visual observation of the characteristic group slowdown time.

In order to eliminate these disadvantages, in the device for measuring the rough deceleration time, containing a selective amplifier with positive feedback, the circuit of which consists of a standard signal generator modulated by the output amplifier, the path under study, and the detector or receiver, B1; to the input of the selective amplifier, it is proposed to supply the auger detector or receiver with an automatic frequency control and provide for a periodic change in the frequency of the standard-sigal-generator and synchronized with the oscilloscope scan.

Due to its use in the described iremiamic device with automatic frequency control, the influence of the intrinsic deceleration characteristic of the measuring circuit on the results of intentions is eliminated, which makes it possible to increase the degree of accuracy and performance measurement. The implementation of a periodic oscillation of the standard-signal-oscillator frequency synchronously with an oscilloscope scan allows visual observation of the characteristic of the slowing down time on the oscilloscope screen. The block diagram and principle of operation of the proposed device is illustrated in the drawing.

The main element of the device, a selective amplifier (3) tuned to the frequency and, is connected to the input of the circuit under study (1) through the standard signal-geerator (2). The output of the investigated CeI (1) through the control receiver (4) (or detector) is connected to the input of the amplifier (3). With an appropriate balance of am. voltages and phases in an observable closed loop (amplifier, standard signal-signaling device, circuit under study, receiver or detector) occur izatuha1111е1; olebaia at frequency -. The high-frequency signal W of the stadient-sigal-generator (2), modulated by the voltage of the frequency-selective amplifier (3), passes through the circuit under study (1) and is fed either to the receiver (4) (when investigating an intermediate retransmission station) or Detector (for intermediate frequency amplifier). Restored on the receiver (4) (or detector) frequency signal - postiyust on the selective amplifier (3). The parameters of the amplifier (3) are prompted in such a way that the value of the geori abstract frequency

-2 pprrdel sts, glapnom way, its contours. However, the parameters of the feedback circuit affect the frequency that is not generated. Thus, the frequency of oscillations arising in the resulting closed net is determined by the total time it decelerates this loop.

When the frequency of the standard-generator oscillator (2) changes by the value of Ds, the ground deceleration time of the test value (1) changes by Do, and the phase of the signal changes by Af z Dz. as a result, the phase balance in the loop is violated, which will cause a corresponding change in the generation frequency by D, ensuring the restoration of the phase balance

d p + j AQ QAs + g; about.

Here f t is the group time for deceleration of the whole chain; t is the group deceleration time of the selective amplifier; 3 - group time delay of the circuit under study.

Thus, the phase shifts occurring in the path under study affect the change in frequency of the measuring oscillator circuit.

By selecting the deceleration time t of the selective amplifier (3) significantly longer than the deceleration time of the circuit under study (1), a linear relationship can be obtained between the change in the generation frequency and the change in the deceleration time Yes yes

T Q where and 2 are constant values.

In order to increase the measurement accuracy and to eliminate the error introduced by the intrinsic deceleration characteristic of the measuring circuit, a receiver (or detector) with automatic frequency adjustment is applied.

To visually observe the characteristics of the depiction (a device (5) is applied, periodically changing the frequency of the standard signal generator synchronously with the oscilloscope sweep (6). A constant oscillation is applied to the vertical deflection plates of the oscilloscope (6)). whose magnitude is proportional to the magnitude and sign of the change of the generated frequency ii. The selective amplifier (3) can be connected either to the detector (7) or to the frequency meter (8), graduated in units of time.

Subject invention

1. A device for measuring the group deceleration time in the high-frequency path of radio-relay lines, containing a selective controller covered by positive feedback, the circuit of which consists of a standard signal generator, modulated by the output voltage of a selective amplifier, the path under study, and a detector or receiver connected to A selective amplifier input, characterized in that, in order to increase the state of the measurement accuracy and to eliminate the influence of the proper time for slowing down the measuring circuit, A vector or receiver provides automatic frequency tuning.

2. A device for measuring the group time of deceleration in the high-frequency path of radio relay lines of clause 1, characterized in that, in order to obtain the image of the deceleration characteristic on the oscilloscope screen, in it the periodic standard-signal-generator synchronous oscilloscope sweeps are often used.

one

Cjtq