SU1226400A1 - Meter of group delay time - Google Patents

Abstract

The invention relates to radio measurement technology and can be used to measure the group delay time of radio devices. The purpose of the invention is to improve measurement accuracy and enhance functionality. To achieve this goal, the mixer includes: mixers 7 and 8, microprocessor 10, registers - information 9 and controls 11, switch 12, frequency synthesizer 13 and control panel register 14. In addition, the meter contains a oscillating frequency generator 1, a modulator 2, detectors 3 and 4, object under study 5, a phase meter 6. At the same time, the phase meter 6 is made on an x-driver x 6.1 and 6.2, trigger 6.3, the coincidence element 6 „4 and counter 6.5 pulses. The microprocessor 10 contains a block 10 ' priority pauses, a central processor 10.2, a random access memory (RAM) 10.3, a constant memory 10.4, and an information display device 10.5. 1 il. (L to to O5 N

Description

The invention relates to radio measurement technology and can be used to measure the group delay time of radio devices.

The purpose of the invention is to improve the measurement accuracy and the expansion function. device capabilities.

The drawing shows a block diagram of the proposed device.

The lag time group meter contains a sweeping frequency generator 1, modulator 2, detectors 3 and 4, phase 5 object under study 5j, mixers 7 and 8, information register 9, microprocessor 10 control register 11, switch 12, synthesizer 13 frequencies and re gis 14 pan ate control

Phase meter 6 contains amplifiers 6.1 and 6.2, trigger € 6 6.3 with separate start, element 6.4 matches and a counter of 6.5 pulses.

The microprocessor 10 contains a block of 10.1 priority interrupt (BPP), a central processing unit (CPU) 10.2, a random access memory (RAM) 10.3, a persistent storage device (ROM) 10.4 and a display information 10.5 (IC);

The oscillating frequency generator 1 is connected to a modulator 2, the output of which is connected to the detector. 3 directly, and to detector 4 through the object under study 5, the first inputs of mixers 7 and 8 are connected to the outputs of detectors 3 and 4, and the outputs to the inputs of phase meter 6, the output of which is connected to the system data bus through the information register 9 microprocessor 10, which is connected via a system data bus via control register 11 to switch 12, through which the second input of modulator 2 is connected to the first two outputs of the frequency synthesizer 13, the third pin of which is connected to the second inputs of mixers 7 and 8, and a quarter to the third in A phase meter module 6, the control output of which is connected to the record input of the information register 9. In addition, a control panel register 14 is connected to the system data bus of the microprocessor 10, the control output of which and the clock input of the oscillating frequency generator 1 are connected to the inputs of the microprocessor 10,

The modulator 2 together with the oscillating frequency generator 1, the switch M 12 and the synthesizer 13 frequencies are designed to form a modulated measuring signal, the detectors 3 and 4 carry out

detecting this signal

Mixers 7 and 8, switch 12 and frequency synthesizer 13 are designed to eliminate the phase-amplitude error that occurs in the channels

phase meter 6 when changing the amplitudes of the input signals in the process of tuning the oscillator 1 oscillator frequency.

Microprocessor 10 is designed

for solving the following tasks: reading and decoding the state of controls through the register 14 of the control panel; controlling the operation of commutator 12 by issuing a corresponding code to control register 11; reading the measurement result from the output of the phase meter 6 through the information register 9 and transmitting it to the CPU 10.2J of calculating the measurement results with error correction and writing them to the RAM 10.3; converting the measurement information into a form that is convenient for its subsequent output to RIA 10.5,

The microprocessor 10 is made, for example, on the basis of the KP 580 microprocessor set,

The synthesizer 13 frequencies form signals with frequencies

uJ-SJ, uJHuJ + SJ., as well as a signal of a quantizing frequency, and contains, for example, three phase-locked loops, synchronized by the voltage of the reference oscillator,

The device works as follows

The group delay time meter operates in the following modes: in the group measurement mode

the delay time with phase-amplitude error correction, the group lag measurement mode with phase-amplitude error correction and the meter's own non-uniformity; the mode of measuring the increments of the group time of the delay; comparison mode measured characteristics of the group

time delay with a reference characteristic.

Let us consider the first mode of operation, the mode of measuring the group time of delay with phase-amplitude error correction, which is set by the operator using the meter control elements. In this case, the pulse from the control output of the control panel register 14, for which, for example, the register K is used, is fed to the first input of the microprocessor interrupt 10 (high priority input). As a result, the BSG 10.1, whose inputs are the interrupt inputs of the microprocessor 10, identifies the interrupt source, in this case, the control panel register 14, and generates an interrupt request signal by which the microprocessor 10 proceeds to the control state analysis subroutine. According to this subroutine recorded in ROM 10.4, microprocessor 10 reads and decrypts the state of the control panel through the register 14 of the control panel to sets the first operating mode. The binary code from the output of the control register 11 is fed to the control input of the switch 12, setting it to the first position. As the switch 12, for example, an K 590 KH1 integrated circuit is used.

The output voltage of oscillator 1 of oscillating frequency 1 with frequency uJ is fed to the first input of modulator 2, for example amplitude, the second input of which in the first position of switch 12 is supplied with frequency voltage 1- + I. From the first output of synthesizer 13 frequency. As a result, an amplitude-modulated measurement signal with a carrier frequency) and an envelope frequency Q are formed at the output of modulator 2. When such a measuring signal is transmitted through the object under study 5, between the envelopes of the signals at its input and output, a phase shift h, proportional to the group lag time of the object under study, 5 ×, 1 (uJ + 5Z) occurs. With a frequency of uJ + Q and a phase shift between them, they are picked up with the help of detectors 4 and 3 (in this case, amplitude ones)

and fed to the first inputs of mixers 7 and 8. At the same time, the second inputs of the mixers 7 and 8 are supplied with the frequency signal LC) from the third output of the frequency synthesizer 13. As a result of frequency conversion, signals are produced at the output of the mixers with an intermediate frequency I. and a phase shift Ч. Phase meter 6 performs measurement

phase shift and converting it to a digital code using quantizing pulses arriving at the third input of phase meter 6 (one of the inputs of the match element 6.4)

fourth output synthesizer 13

Frequencies. As a result, a digital codeN.,, is generated at the information output of the phase meter 6 (the discharge outputs of the counter 6.5 impulses:)

(torsional phase shift

Ф М .h- U Н

where H, is the phase shift between the frequency envelopes u) + Q.; the phase-amplitude error that occurs in the channels of the phase meter 6 due to the fact that in the process of frequency tuning the level of the signals arriving at one of the inputs of the phase meter 6 changes as The transmission coefficient K (s) e) of the objects under study can substantially depend on the frequency. After the completion of code formation N, proportional to the phase shift 4 /, the recording signal coming from the control output of the phase meter 6, for example, a pulse from the trigger output 6.3, this code is written into the information register 9. As this register, for example, the multimode buffer register K 589 of the IL 12 is used. The ready signal, appearing at the output of the information register 9 after the recording is finished, the code N is placed in the central process Op 10.2. Then, the microprocessor 10 sets the switch 12 to the second position through the control register 11, in which the second input of the modulator 2 is supplied with the frequency signal uj - Q from the second output of the 13 frequency synthesizer. The operation of the meter in the second position of the switch 12 is similar to its work in the first position. First, using the oscillator 1, the oscillator often

and modulator 2, an amplitude-modulated measurement signal is generated with a carrier frequency uJ and a frequency envelope jJ -SI, then the envelopes uJ - - Q are selected, the phase shift H between which is proportional to the measured group delay time t (). After measuring and encoding the phase shift on the information output of the phase meter 6, a code N is formed, proportional to the phase shift - /

 - -.

lh

where M is the phase shift between the frequency envelopes uJ-J (the sign of the phase shift at the input of the phase meter 6 changes in comparison with the first position of the switch 12, since the frequency uJ at the second inputs of mixers 7 and 8 is higher than the frequency uJ - Si at its first inputs).

In this case, the phase-amplitude error of the PM remains the same, since with detailed reproduction of the studied characteristic of the group delay time during the measurement time of one of its discrete points, i.e. in both positions of the switch 12, the phase and, therefore, the amplitude of the signal at the inputs of the phase meter 6 remain almost unchanged

The code Nj of the measurement result of the phase shift H is placed in U 10.2. After that, the microprocessor 10 calculates the difference of two measurements of the phase shift in one and in the other positions of the switch 12, and also performs the operation of dividing by two the obtained result:

(Y, -Yj / Z (4, A) - () / 244%) Since the modulating frequencies uJ + and uJ - O. are located symmetrically with respect to the frequency uJ and differ from it, by a low intermediate frequency I, phase shifts envelopes with frequencies uJ + I. and at the output of the object under study 5 are almost equal (i: -f, and their sum corresponds to twice the phase shift value v of the envelope with the average frequency

uJ4CuJ -S2) Hu; -ni) / 2, that is, H, U, 2 f „.

Thus, after processing with a microprocessor 10

five

0

five

0

five

0

five

0

five

the measurement of the measurements is carried out correction of phase-amplitude error and in the RAM 10.3 is placed the result code N, proportional to the phase shift

,.: - Po - (H, -% V (, + 4 J / 2,

and, accordingly, the group delay time of the object under study 3 at the frequency uj of the oscillating frequency generator 1, since

.t-4 / cJ - 4, / oJ Q-- fjfa; -Sl.

At the same time, the resulting KodM поступ enters PIO 10.5.

The group time of the object under study 5 at other frequencies in the operating range is measured similarly. Consequently, during the forward course of tuning the oscillator 1, the oscillating frequency in RAM 10.3 contains codes for the measurement results of the group delay time Ij in the frequency range, i.e. the frequency characteristic of the group latency of the object under study 5, which is simultaneously indicated on RIA 10.5 in a form convenient for the operator.

At the end of the direct frequency tuning run, the sync pulse from the sync pulse output of the 1st frequency channel is fed to the second microprocessor interrupt input JO (low priority input). As a result, PPO 10.1 generates a request signal. According to this signal, microprocessor 10 stops executing the measurement program, sets switch 12 to the first position, and after the clock pulse ends, returns to the beginning of the measurement program of the first mode.

Consider the operation of the meter in the second mode, the mode of measuring the grouped lag time with correction of the phase-amplitude error and the inherent unevenness of the meter, which is set

similar to the first mode.

In this mode, the measurement is performed in two stages. At the first stage, the meter measures its own non-uniformity (calibration). In this case, the object under study 5 is disconnected from the meter, and the detector 4 is connected directly to the output of the modulator 2. Operation

The device at this stage fully corresponds to its operation in the first mode. Codes N of the results of measuring the intrinsic non-uniformity of the group time of the meter in the frequency range (frequency response) are placed in RAM 10.3.

At the second stage, the object under study 5 is connected to the meter again and the measurement is carried out.

group latency

J

including the group lag time of the object under study and the intrinsic unevenness of the meter and,. The operation of the device at the second stage is similar to its work at the first stage. Codes corresponding to Lj are placed in RAM 10.3.

The microprocessor 10 calculates the group delay time values of the object under study 5 in the frequency range - LCJ and places the corresponding codes in the RAM 10.3. The received results come to PIO 10.5. In addition, at the request of the operator, the frequency characteristic of the meter’s own irregularity

Thus, as a result of taking into account the intrinsic unevenness of the meter, the measurement accuracy is further increased.

In the third mode of operation — the measurement mode of increments and the group delay time L i-, which is set similarly to the first two modes, the change in the group delay time in the frequency range relative to the selected L value is determined, for example, at the initial oscillator frequency 1 measurement results obtained in the second mode of operation are used. The microprocessor 10 calculates the differences d1 i, -4-4 determines their sign and places the corresponding codes in the RAM of the OS. Then the results of the calculations go to PIO 10.5.

In the fourth mode, the measurements of the characteristics of the group lag time of the object under study 5 are compared with the reference characteristics placed, for example, in the ROM 10.4. In this mode, microprocessor U calculates deviations Atj

second mode I measurement results

Kj

relative to the reference .ui. determines their sign, and

3J K-J

also puts the corresponding codes in the RAM 10.3. Then microprocessor 10 outputs the results of the calculations to SPD 10.5 for indication.

In order to further increase the measurement accuracy, the measurement results are averaged, which are programmed in the same way in all four modes of operation. For this, the microprocessor U accumulates in the RAM 10. Zp of the results of measurements of one point of the frequency response of the group time of the object under study 5, performs the operations of summing the results of these measurements and dividing the sum obtained by and 1 -n

-1-1

l

where L is the average value of the group

lag time at the studied point of the characteristic

the value of the group delay time obtained in the i-th dimension h is the number of measurements. Similarly, the measurement of other points of the frequency characteristic of the object under study 5 is carried out.

In addition to the amplitude modulation of the measuring signal discussed above, the device can use balanced or frequency modulation. In this case, the operation of the device does not change, but only the principle of forming the measuring signal and the allocation of signals of modulating frequencies, i.e. modulator 2 and detectors 3 and 4 are changed.

In the group latency meter, the phase-amplitude error is reduced by microprocessor processing the results of two measurements obtained at different modulating signal frequencies, i.e., the measurement accuracy is improved, and the group latency time is measured, its increments are compared and the characteristics of the test are measured and reference objects, i.e.

the functionality of the proposed device is expanded. In addition, due to the use of a microprocessor, the measurement accuracy is further increased by eliminating the intrinsic non-uniformity of the device from the measurement result,

Claims (1)

Invention Formula A group time lag meter containing a sweeping frequency generator connected to a modulator whose output is connected to one detector directly and to another via terminals to connect the object under study, as well as a phase meter, characterized in that, in order to improve the accuracy of measurement and expansion of functional capabilities, it introduced two mixers, information register, microprocessor, control register, switch, synthesizer Editor E.Papp Order 2130/46 Compiled by M. Katanov Tehred I.Popovich Proofreader T.Kolb Circulation 398 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 frequency and control panel register, the first inputs of the mixers are connected to B; the outputs of the corresponding detectors, and the outputs - to the inputs of the phase meter, whose output is connected to the system data bus of the microprocessor through the information register through the control register C: the switch, the output of which is connected to the modulator, and the other two inputs of the switch is connected to the first two outputs of the frequency synthesizer, the third output of which is connected to the second inputs of the mixers, and four It is connected to the third input of the phase meter, the control output of which is connected to the input of the information register, besides, the control panel register is connected to the system data bus of the microprocessor, the control output of which and the clock output of the oscillating frequency generator are connected to the inputs of the microprocessor switches.