SU1698834A1 - Narrow band two-port devices tuner - Google Patents

Abstract

The invention can be used in the development of instruments for tuning and controlling the phase-frequency characteristics of narrow-band quadrupoles. The purpose of the invention is to expand the range of measured angles, achieved by dividing the frequency of the signal with the output of the measured 4 and the reference 5 four-terminal networks. For this, the first 31, second 32 and third 33 binary frequency dividers, the first 34, the second 35 and the third 36 multiplexers and the controlled frequency divider 37 are introduced into the device. When the device operates, the signal from the outputs of the first 34 and second 35 multiplexers through the converters 8 and 9 is the phase-time interval, the first 10 and second 11 time-code converters arrive at the calculator 15 of the code difference, the output of which is connected to the first input of the oscillographic indicator through reference element 18 21, the first 19 and second 20 digital-to-analog converters are connected to the scan inputs. The synchronization and control of the units of the device is carried out by the control unit 22. 2 Il. with

Description

The invention relates to radio-measuring technology and can be used in the development of devices for tuning and monitoring the phase-frequency characteristics of narrow-band four-terminal devices.

The purpose of the invention is the expansion of the range of measured angles.

Figure 1 shows the structural diagram of the device; in FIG. 2 - time diagrams of individual blocks.

The device contains a fixed frequency generator 1, tunable generator 2, balanced modulator 3. measured 4 and reference 5 four-port, first 6 and second 7 frequency mixers, first 8 and second 9 converters phase shift - time interval, first 10 and second 11 converters time interval - a code, each of which contains a quantization block 12, a counter 13 and a memory register 14, a code difference calculator 15, an input of 16 device tolerance bits, a register 17, a comparison element 18, the first 19 and second 20 digital-to-analog converters, oscill a graphic indicator 21, a control unit 22, comprising a first 23 and a second 24 frequency dividers, a phase detector 25, an adjustable oscillator 26, a timing unit 27, a binary counter 28, the first 29 and second 30 delay elements, the first 31, second 32 and third 33 binary dividers, first 34, second 35 and third 36 multiplexers, controllable frequency divider 37, input 38 bits of the measuring range of the device, and the output of the first mixer 6 frequencies connected to the first input of the first converter 8 phase shift - time interval in series with the first binary divider 31 and the first multiplexer 34, the output of the second frequency mixer 7 is connected to the first input of the second converter 8; the phase shift is the time interval through the second binary divider 32 and the second multiplexer 35 connected in series; the output of the fixed frequency generator 1 is connected to the second input of the first 8 and the second 9 phase shift converter - the time interval through the third binary divider 33 and the third multiplexer 36 connected in series, the first output of the control unit 22 through the controlled de the frequency suppressor 37 is connected to the first control input of the first 8 and second 9 converters; the time interval is a code, the control inputs of the first 34, second 35, and third. 36 multiplexers and a controlled frequency divider 37 are connected to the input of 38 bits of the measuring range of the device.

The device operates as follows.

Before starting the measurements, input code Idop is supplied to input 16, and the frequency F _{o of the} generator 1 and the frequency f of the generator 2 are selected from the relation f + F ₀ = fcp, (1) where f _C p is the average frequency of the measured 4 and reference 5 four-terminal devices.

During measurements, the frequency f of the tunable generator 2 varies within Δί ₃ Λ6 of the passband of the four-terminal 4.

At the output of the balanced modulator, we have a signal

Ui = U mi [cos2 π (f-Fo) t + cos π 2 (f + F ₀ ) t], (2) where U mf is the oscillation amplitude.

After passing the signals through both four-terminal networks at their outputs, we have, respectively

U2 = and m2 [cos2 π (f + Fo) t + prism]. (3) 11s = and ts [cos2 π (f + Fo) t + φ arr]. (4) where U tg <U tz are the oscillation amplitudes;

φ ism, φ arr are the phase shifts introduced by the four-terminal networks 4 and 5, respectively.

At the output of the mixers 6 and 7, respectively,

LM = U t4 cos (2 π F _o t + <p _meas ), (5)

U5 = U ms .cos (2 π F _o t + у? Arr), (6) where U t4, U te are the oscillation amplitudes.

The measured quantity is the phase shift difference

AutT = y? Ism ~~ <f> ar

In converters 8 and 9, phase shifts are converted into time intervals (phase intervals τφ), which are then converted into codes in converters 10 and 11, respectively

Νμ3μ ⁼ Κ y? rev; Νο6ρ = Κ φ arr. (8) where K is the conversion coefficient.

The calculator 15 determines the difference code

Δ Ν = Νμ3Μ ~ Νο6ρ, (9) which in the comparison element 18 is compared with the tolerance code N _ftOrI .. applied to the information input of the register 17 from input 16.

If ΔΝ> Ν _Λ οπ ·, the signal arriving at the output of the comparison element 18 appears on the 'modulator Ζ of the cathode ray tube of the oscilloscope indicator 21 for the brightness modulation of its beam.

Adjustable generator 26 generates oscillations of the quantizing frequency f ₀ and is synchronized with the frequency of the generator 1 using a phase detector 25, the inputs of which are signals with a frequency

F <M, f o »Fo. (10) where Κι, К ₂ are the division coefficients of the first 23 and second 24 frequency dividers, respectively. Moreover, the fractional part of the ratio of the frequencies of the generators 1 and 2 should be selected from the condition of optimal quantization

F _o K p F o T ISM '; ^J where d and K are coprime numbers having a common factor equal to one:

p is the number of half-periods of the signal F _o used for measurement (P is 1 or 2);

Tism - the time interval of measurement formed by the timing unit 27 (Fig.2, a):

K = pF ₀ Tm3m is the number of averaged phase intervals on the Tism segment.

The first 29 and second 30 delay elements form pulses of synchronization and zeroing, respectively, of the memory register 14 and counter 13. These pulses (Fig.2, b, c) are shifted in time from each other and relative to the trailing edge of the pulse Тиз.

The signals from the outputs of the control unit 22 are supplied to the measuring and reference channels of the device. In the measuring channel in the quantization unit 12, which is part of the transducer 10, the phase intervals Χφ formed in the transducer 8 during the time Tm. are filled with quantizing pulses from the generator 26 and are counted by the counter 13. At the end of the interval Tism. by the command of the synchronization pulse from the output of the first delay element 29, the contents of the counter 13 are transferred to the memory register 14. The delayed pulse from the output of the delay element 30 resets the counter 13, after which the converter 10 is ready to process information for the next interval Tism.

The converter 11, located in the model channel of the device, works similarly.

The binary counter 28 is controlled by the signals of the timing unit 27. The states of the counter 28 are cyclically repeated and can take values from 0 to M = 2 ^t , where t is the number of bits of the counter 28, determined by the necessary approximation accuracy of the measured four-terminal 4. The output code of the counter 28 is input to the first digital-to-analog Converter 19, the output voltage of which is supplied to the horizontal channel X of the oscilloscope indicator 21 and to the control input of the tunable generator 2, causing a change in its frequency to My research DTzd band.

To each interval Tism. corresponds to a certain value of the frequency of the generator 2, as well as the value of the code M _And zm generated in the converter 10 and supplied to the input of the second cirophonic-analog converter 20, the output voltage of which is supplied to the vertical channel of the oscilloscope indicator 21. In this case, the phase-frequency signal will be cyclically displayed on the screen of the indicator 21 the characteristic of the measured four-terminal network 4, consisting of points, some of which in the case Δ N> b1 _DO p (i.e., when Δ <ρ> φ add) will have noticeable brightness marks,

The operation of monitoring and tuning the measured four-port 4 consists in achieving on the screen of the indicator 21 such an image of a phase-frequency characteristic, in which there are no brightness marks.

When measuring the phase-frequency characteristics of quadripoles with a total phase shift of more than 360 ° in the Δ fsflS study band, the ambiguity of reference appears due to the limited phase characteristic of the transducers 8 and 9, the phase shift is the time interval.The method of eliminating the ambiguity of measurements is based on the principle of reducing phase shifts during frequency division working signals, in which the phase shift decreases by a factor of ^ ^ раз times, equal to the division coefficient. At the same time, the frequency of the quantizing pulses must be increased, so that the phase shift count corresponds to a wider measurement limit.

For this purpose, a controlled frequency divider 37, binary dividers 31-33 and multiplexers 34-36, controlled by the code from input 38, are introduced into the device.

In the general case, when the device has n limits for measuring the phase shift 0 ... 360 ⁰ ; О ... 72О ⁰ ; 0 ... 1440 °; ..., then for an arbitrarily chosen ί-th limit according to the code from input 38 at the input of the controlled frequency divider 37 has a frequency signal (12) 4 ^{P 1} and at the output of all multiplexers 34-36 we have frequency signals (13) (14) where 1 = 1,2,. ,,

Obviously, when working on the I-th limit, the fractional part of the frequency ratio is

NTNM ^{2_2 +} ' ⁺¹ and satisfies the condition of optimal quantization, i.e. corresponds to high accuracy and speed of measurement.

As an example of implementation, we consider a device having n = 2 measurement limits 0 ... 360 ^ and О ... 72О ⁰ , designed to measure the phase-frequency characteristics of quadripoles with a passband DTzB 10 kHz and a squareness coefficient Kpr ^ 5.

Generator 1 has a fixed frequency

F _o > CR. AGzDB = 500 kHz. (fifteen)

Choosing Τμ3μ · = 2.88.10 ' ³ s at p = 2, we have

K = p F _o Tm3m = 2880,

When the device is operating at the first limit Q ... 360 ° according to the corresponding input code; of the bus 38 at the outputs of the multiplexers j 34-36 there are signals of frequency F _o . At the same time, at the output of the controlled frequency divider 37, we have a quantizing signal (frequencies fo / 4. The voltage diagrams corresponding to the work at the first limit are shown in Figs. 2, d, e, e, s.

When the device is operating at the second limit 0,. 720 ° according to the changed code of the input bus 38, the signals of the frequency F _o / 2 are present at the outputs of the multiplexers 34-36, and at the output of the controlled frequency divider 37 we have a quantizing frequency f ₀ . The voltage diagrams corresponding to the work on the second limit are shown in Figs. 2g and, k, l.

Using relations (11) and (14), as well as the condition fo »Fo, we find for the tunable generator 26 the frequency value fo = 10 000 694, 4 (4) Hz. Phase detector 25 operates at a frequency Гф _Д = 694.4 (4) Hz, and frequency dividers 23 and 24 should have division factors Κι = 720 and Кг = 14401, respectively.

For the limit 0 ... 360 ° we have:

a) the number of averaged phase intervals in the interval T _FROM m

K | = P Fl Thism = 2.5-10 ⁵ 2.88 10 ' ³ = 2880:

b) the fractional part of the frequency ratio (f кЫ1_ d 1 _ 1..

| F G / ^- Κι 2880 ' ^{α 1}

c) the maximum number of pulses elapsed during the time Tism. on the counter 13 = 0.8 °;

co20 measurements for the limit dii = 4;

N ISM - 2 'f ^KV 1 T ^{IEM -} * 2.5 Ί0 ⁶ * 2.88 * 10 ~ ³ = 3600:

d) the measurement error at optimal quantization is d 1 360 ° ^σ ° ^πτ1 = .......... 1.-360 ° .. 0.01О _;

V6 2880 - 2.5 · 10 ⁶

d) measurement error in classical quantization: equal to "sq1" meas.

e) the gain in accuracy sets

R = - ^ = 80 times.

(U opt1

A similar calculation of 0, .. 720 ° gives the values

Kts = 1440; I

F and) K and 360 A1ism. = 720; sGoptN ^k = 0.02 °; (J _X L11 ~ 0.26 ° R = 14.

The calculation shows that on both measurement ranges at small measurement times, Tism provides high measurement accuracy.

Claims (1)

Claim A device for tuning narrow-band quadripoles containing a tunable generator, connected to the first input of the balanced modulator and the first inputs of the first and second frequency mixers, a fixed-frequency generator connected to the second input of the balanced modulator, the outputs of which are connected to the corresponding inputs of the model and measured four-pole, outputs of which connected respectively to the second inputs of the first and second frequency mixers, the outputs of the first and second converters phase shift - the time interval is connected to the inputs of the respective converters time interval is the code, the outputs of which are connected to the inputs of the calculator of the difference codes, the control unit, the first and second digital-to-analog converters, the register, the comparison element, the input bits of the device tolerance, an oscillographic indicator, and the input of the control unit is connected to fixed frequency generator, the second, third and fourth outputs of the control unit are connected respectively to the second, third and fourth control inputs of the first and second time interval - code, the fifth output of the control unit is connected to the input of the first digital-to-analog converter, the output of the difference code calculator is connected to the first input of the comparison element, the input of the device tolerance bits is connected to the register information input, the register output is connected to the second input of the comparison element, the output of which is connected with channel Z of the oscilloscope indicator, the horizontal and vertical channels of which are connected to the corresponding outputs of the first and second digital-analogue converters zovateley, the input connected to the output of the last inverter of the first time interval - the code, and the control input of the tunable oscillator coupled to the output of the first digital to analog converter, wherein; that, in order to expand the range of measured angles exceeding 360 °, the first, second and third binary frequency dividers, the first, second and third multiplexers, a controlled frequency divider, the input of the digits of the measuring range of the device are additionally introduced into it, and the output of the first frequency mixer is connected to the first input of the first phase shift converter is a time interval through the first binary frequency divider and the first multiplexer connected in series, the output of the second frequency mixer is connected to the first input of the second phase shift converter - time interval through the second binary frequency divider and the second multiplexer connected in series, the output of the fixed frequency generator is connected to the second inputs of the first and second converters phase shift - time interval through the third binary divider and the third multiplexer connected in series, the first output of the control unit via controlled the frequency divider is connected to the first control inputs of the first and second converters time interval is a code that controls in ode first, second and third multiplexers and controllable frequency divider coupled to the input device discharges measurement range. a G ----- * I ------------------ 1 --------------------- 1 1 ----------------------- 1 B ( 1 _ 8 > ¹ Τί- AND * - ** 1 1 Tm m TO L to----- 1-1 R ~ 1 ΓΊ Γ ~ Ί 1 1 J ---- to Central Research Institute mini IIIIUIL IM FIG. 2