SU1486982A1 - Device for measuring phase time of four-terminal network delay - Google Patents

Description

The invention relates to a radio measuring technique. To extend the frequency range, a constant frequency signal is introduced, which is obtained from the generator frequency 9 using a frequency divider 10 and a low-pass filter 1 и and the phase change of which is used by phase shifter 12 to compensate for phase changes in the studied

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quadrupole 5. The test signal supplied to the input of quadrupole 5 is generated using a single-sided modulator 2 from tunable generator 1 and 3 signals, the frequency Ω of the low-frequency generator 3 being measured by a frequency meter 29. The frequency signal ω — Ω from the input and output of the four-pole 5 using balanced mixers 6, 8, 13 and filters 7, 14, 15 low frequencies in one channel and balanced mixers 19, 21, 23 and filters 20, 22, 24 in the other channel is converted so that at the outputs of these channels was obtained frequency Ω modulation. Further, the signals are limited with the help of limiting amplifiers 16, 25 and filters 17, 26 and multiplied in multiplier 18. The integrator 27 selects a constant component, which is minimized with the help of an indicator 28, thus providing measurements in a compensatory manner. 1 il.

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The invention relates to a radio measuring technique and can be used to measure with high accuracy the phase delay time and the phase constant of the quadrupoles with a large attenuation, operating in a wide frequency range.

The purpose of the invention is to expand the frequency range while maintaining the required accuracy of measurements of the phase time delay of quadrupoles with a large attenuation.

The structural diagram of the device for measuring the phase time delay is shown in the drawing.

The device contains a tunable high-frequency generator 1, an output connected to the second input of the single-sided modulator 2, the first input of which is connected to the output of the tunable low-frequency generator 3, the output of the single-sided modulator 2 through the serially connected amplifier 4 with automatic gain control and the quadrupole 5 under study is connected to the first input the first balanced mixer 6, the second input connected to the output of a tunable high-frequency generator 1, the output of the first balanced mixture 6 through the first low-pass filter 7 is connected to the second input of the third balanced mixer 8, the first input of which is connected to the output of the high-frequency generator 9 of a fixed frequency through the serially connected frequency divider 10 and the fifth low-pass filter 11, whose output through the phase shifter 12 is connected to the second input the fourth balanced mixer 13, the first input connected to the output of the third balanced mixer 8 through the sixth filter 14 low frequencies, the output of the fourth, balanced mixer 13 through a sequence The seventh low-pass filter 15 is connected, the first amplifier-limiter 16 and the second low-pass filter 17 are connected to the first input of the multiplier 18, the second balanced mixer 19 is connected to the output of a high-frequency tunable oscillator 1 and the output of the amplifier 4 with automatic gain control, the second balanced output the mixer 19 through the third low-pass filter 20 is connected to the second input of the fifth balanced mixer 21, the output of which is connected to the second input of the sixth balance through the eighth low-pass filter 22 the first inputs of the fifth 21 and sixth 23 balanced mixers are connected to the output of the fifth 11 low-pass filter, the output of the sixth balanced mixer 23 through the ninth low-pass filter 24 connected in series, the second amplifier limiter 25 and the fourth low-pass filter 26 are connected to the second input of the multiplier 18, the output of which through the integrator 27 is connected to the indicator 28, the digital frequency meter 29, is connected to the output of the tunable low frequency generator 3.

The device works as follows.

The high-frequency voltage ί / ι (/) = ί ^ Χ ΧΓ05 (ω / + φι), whose frequency can be tuned in the required frequency range, is fed from the output of a tunable high-frequency generator 1 to the second input of a single-sided modulator 2, where it is subjected to a single-sided modulation with LOW voltage frequencies,

arriving at the first input of a single-band modulator 2 from the output of a tunable low-frequency generator 3. As a result of single-sided modulation, the frequency ω of the high-frequency voltage decreases.

or increases by the magnitude of the modulating frequency Ω, i.e., depending on the setting of modulator 2, the output frequency is ω — Yili ω + Ω When tuned to the lower sideband, the high frequency voltage takes on the form of (/) = and „, all $ [ (w—

- Ω) + φι - fg], where φ, and fg are initial

phase shifts of high-frequency and low-frequency voltages. This voltage passes through the amplifier 4 with automatic adjustment of the gain to the input of the studied quadrupole 5 with a phase delay Δτ. The output voltage of the studied quadrupole is C / ₄ (/) == / C | χ X and _t cws $ [(ω — Ω) (I — Δτ + φι - φ ₂ ] multiplied in the first balanced mixer 6 with high-frequency voltage Πι () As a result of the multiplication of these voltages, the output voltage of the first balanced mixer is 6 =75 () = / ίιΠ _ίη ιΠη! 3ί05 (ω / + φι); 05 [(ω — ΩξΖ -

- Δτ) + φι - fg], where Κι is the transmission coefficient of the quadrupole under study 5, is filtered using the first 7 low-pass filter, the component with the modulation frequency Ω υ <ί (ϊ) = Κ \ Κ2υ _t1 and _t ХX Χό05 [έ > Ζ + (ω – Ω) Δτ — φ ₂ ), where Κ · 2 is the transfer coefficient of the first low-pass filter 7.

At the same time, the voltage B + C is fed to the second input of the third balanced mixer 8, where it is multiplied with the voltage ί / ₇ (7) = co-C (Ω-ί-Oz) / C-fz], which is formed from the voltage coming from the high-frequency output generator 9 fixed frequency using frequency divider 10 and the fifth low-pass filter 11 and is fed to the first input of the third balanced mixer 8. The division factor of frequency divider 10 is chosen so that the signal frequency at its output is approximately twice the modulating frequency Ω.

As a result of voltage multiplication {7b (Ts and and ₇ (D), the output voltage of the third balanced mixer _t \ X

X U t s and _t 7 S O 5 {I Ω + Ωο) / -f 3] C05 [Ωο (+ ω -

- Ω) Δτ + φ ₂ ], where fz is the initial phase voltage shift υ ~ ().

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From the voltage U $ (1), using the sixth low-pass filter 14, the component with the frequency Ω is extracted)

At e (1) = K I K2 K3 U t I and _tZ and _m7 CO5 [ΩοΖ - (ω - —Ω) Δτ + φ ₃ —φ ₂ ],

where Ks - the sixth filter transmission coefficient of the 14 low frequencies.

In addition, the voltage £ / ₇ (Ζ), coming from the output of the fifth low-pass filter 11 through the phase shifter 12, which is initially set to the zero position, is fed to the second input of the fourth balanced mixer 13, the first input of which is supplied with a voltage of 6/9 (/ ) As a result of multiplying these voltages, the output voltage of the fourth balanced mixer 13 is expressed by the formula

У1θ (/) = Κ | Kylesb / t! itzU t7 SO z (((Ω + Оо) 1 + fz] X Xsoz [ΩιΑίω — Ω) Δτ + φ _{3 -} fg].

From the voltage ί /, ο (Ζ), a component with the modulation frequency Ω is also distinguished using the seventh 15 low-pass filter

Y 1} (1) = КХ ^ UKZU t \ Y tzU t7SOz (Ω / -} - (ω - Ω) Δτ- | + Cf2].

Voltage 6 / C (/) is fed to the input of the first amplifier-limiter 16. The limited voltage through the second low-pass filter 17, designed to restore the sinusoidal waveform and limit the effect of higher harmonics on the measurement result, is fed to the first input of the multiplier 18.

In the reference channel, the voltages ά / ι (Ζ) and Y (1) are fed to the inputs of the second balanced mixer 19, the output voltage of which is described by the formula

6 / | 2 (0 = 6 / _r | 6 / _m3 SO5 (m / Q-1 +) SO5 ((ω - Ω) / +

+ φι —φ ₂ ].

From the voltage spectrum [/ 12 (/) with the help of the third low-pass filter 20 a component is selected with a modulation frequency Ω

V \ s (1) = KlU t \ and _t ZSO $ (O1 - \ - y2),

where Χ.ί is the transfer coefficient of the third low-pass filter 20.

Voltage _6/7 (/) and ί /] ₃ (Ζ) applied to the inputs of the fifth balanced mixer 21, the output voltage of which takes the form

y I ¢ (1 -) - _t \ and _t communication tsoz _m ((Ω- Ω3) / - ι -φ _3] x

Χεθί (ΩΖ + φ ₂ ).

Using the eighth 22 low-pass filter, the component with frequency Ωο is separated from the voltage ί / ι ₄ ()

and \ s (1) = K ^ Y _t \ and tzU t7C08 (Oo1 + ^ 3 - φζ)

Voltages ί / ₇ (Ζ) and 6/15 (/) are fed to the corresponding inputs of the sixth balanced mixer 23, the output voltage of which is described by the formula

and \ s (1) = K 4 it \ UtzU t? C05 [(Ω - | - Ωο) —fz] X

Χϋθ5 (Ωο / + φ ₃ —φ ₂ ) From the voltage ί / ιβ (^), a component with a modulation frequency Ω is also extracted using the ninth 24 low-pass filter

Y-P ^ —KaU t1 Y tzU t7CO $ (O1 Ή ψ ₂ ).

Voltage £ 7ι- (Ζ) after amplitude limitation with the help of the second amplifier-limiter 25 and filtering by the fourth low-pass filter 26 is fed to the second input of the multiplier 18. In multiplier 18, the multiplication of voltages 6 / c (g) and Y \ - (1 ) with the subsequent integration of the resulting work with the help of the integrator 27

У1 δ (/) = 5 У1 1 (1) У 17 (1) (11-К \ КзКзК4Ут1 У тзХ X υ '! _Η γεο8 (ω - Ω) Δτ.

Selected at the output of the integrator 27 constant voltage is fixed by the indicator 28.

By reducing the modulation frequency Ωλο of the value of Ωι, which is measured by the digital frequency meter 29, one obtains the zero value of the integrated voltage, which corresponds to the condition:

with·

C08 (a> —Ωι) \ τ = ε03 ^ - · (1)

Shifting the phase of the high frequency voltage _6/7 (/) a fixed frequency Ω + + Ωο via the phase shifter 12 by a phase angle Δφ. After multiplying the voltage and $ (1), coming from the output of the sixth low-pass filter 14, with the voltage Y- (1) at the output of the seventh 15 low-pass filter, the modulation frequency component Ωι is

u'i (1) = K1K2KzU, t Y, „HUt7Soz \ Ω | / + (ω -

- Ωι) Δτ + φ ₂ —Δφ],

Re-reduce the modulation frequency Ω to a value of Ω ₂ to get

zero value of the integrated voltage, which corresponds to the condition

C05 [(0) —Ω ₂ ) Δτ - Lf] = CO5 ~ - · (2)

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Equating the left sides of expressions (1) and (2), we obtain the expression for the phase delay time

l _{m ==} ^ p £ ra ^d ) ₌ Δφ ± ΡΛΛ) __

Ω, -Ω ₂ 2π (Γ, - ^ ₂ ) · '

where Р \ and Р-2 are the frequencies of the modulating signal.

By changing the frequency ω of the high-frequency tunable generator 1 within the passband of the quadrupole under study 5 and specifying phase shifts Δφ using the phase shifter 12, one can calculate the value of Δτ for each frequency.

The phase constant of the quadrupole 5 under study can also be determined for each frequency ω from the expression

R

β = ωΔτ = 2π / · ~ οΔτ = ° „Δφ, g \ -g-2

where Pn is the variable frequency of the high-frequency signal.

The uniqueness of the measurement of the phase time delay by the frequency difference P \ —P2 and the phase shift Δφ is provided (as in the prototype) when these values are selected within

10δφ <Δφ <^;

10δφ <(θ, -5? ₂ ) Δτ ^

where δφ 'is the sensitivity threshold in the phase of indicating the zero value of the integrated signal;

. \ τ _{Μ1> £} . - the maximum value of the phase time delay of the investigated quadrupole 5.

In accordance with the specified conditions, the initial value of the modulation frequency and the input phase shift must be selected from the following relationships:

R *

‘Ϊ́ = ΡΓ’

TL I Mahsh

Δφ = ^.

Claims (1)

Claim A device for measuring the phase time delay of quadrupoles, containing a high-frequency generator of a fixed frequency and a tunable low-frequency generator, the output of which is connected to the first input of a single-band modulator, the output connected via eight serially connected amplifier with automatic gain control and a quadrupole under study to the first input of the first balanced mixer, the output of which is connected to the input of the first low-pass filter, phase shifter, first amplifier-limiter, output connected through the second low-pass filter to the first input of the multiplier, second balanced mixer Con first input to the output _W ene amplifier with automatic gain control, and the output - to the input of the third lowpass filter, a second amplifier-LIMIT ohchitel output connected through the fourth filter lower ) 5 frequencies to the second input of the multiplier, the output of which through the integrator is connected to the indicator, a digital frequency meter, the input connected to the output of a tunable low-frequency generator, characterized in that, in order to expand 20 frequency range while maintaining the required accuracy of measurements of the phase time delay of four pole members with a large attenuation, it has been additionally introduced tunable high frequency generator 25 four balanced mixers, five low-pass filters and a frequency divider, with a tunable high-frequency generator output connected simultaneously to the second input of a single-sided modulator and to the second inputs of the first and second balanced mixers, the third balanced mixer with the first input connected to the output of the first low-pass filter, and the second input - to the output of the fifth low-pass filter, the input connected to the output of the high-frequency generator fixed 35 frequency through a frequency divider, the output of the third balanced mixer through the sixth low-pass filter connected to the first input of the fourth balanced mixer, the second input of which is connected to the output of the phase shifter, the input connected to the output ^{4 and the} fifth low-pass filter, the output of the fourth balanced mixer through the seventh low-pass filter is connected to the input of the first amplifier-limiter, the fifth and sixth balanced mixers are connected to the output of the fifth low-pass filter at the same time, the second input of the fifth balanced mixer is connected to the output of the third filter low-pass, the output of the fifth balanced mixer through the eighth low-pass filter is connected 50 to the second input of the sixth balanced mixer, the output of which is connected via the ninth low-pass filter to the input of the second limiting amplifier.