SU1291895A1 - Device for generating signal with given harmonic coefficient - Google Patents

Abstract

The invention relates to the technique of electrical measurements and can be used to test nonlinear distortion meters. The purpose of the invention is to improve the accuracy of setting the harmonic coefficient by eliminating the error of comparing on the rms value of the voltage of the first and higher harmonics. For this, a pulse generator 2 connected in series, a second adder 3 and a spectrum analyzer 6 are additionally inserted into the device. The device also comprises a sinusoidal signal generator 1, a precision divider 4 and a first adder 5. Both adders are made identical. The calibrated harmonic coefficient (K) is given by divisor 4, which can be calibrated in terms of, K. 1 il. c (O (L

Description

The device relates to a radio measuring technique and can be used to calibrate nonlinear distortion meters.

The purpose of the invention is to improve the accuracy of setting the harmonic coefficient by eliminating the error of comparing on the rms value of the voltage of the first and highest harmonics.

The drawing shows a block diagram of the device.

The device contains a sinusoidal signal generator 1, a pulse generator 2, a second adder 3, a precision voltage divider 4 and a first adder 5, the second inputs of adders 3 and 5 are connected to the output of the generator 1, and the output of the adder 3 is also connected to the generator 6 . The adders 3 and 5 are identical.

The device works as follows.

Original sinusoidal signal from generator 1

U {t) and sin iJt

(one)

arrives at the clock input of the generator 2, which generates a rectangular signal U, (t) with amplitude and,. The signals U (t) and) are summed in adder 3:

Uj-ct) u (t) + u (t)

(2)

The generator 2 sets the duty cycle of the signal U. (t), equal to two. Over-40 topics change the signal delay U, (t) and the signal amplitude U (t), respectively, by adjusting the oscillators 1 and 2 until the first harmonics of these signals are compensated: 45

and) - 4 / L.- U, sin o) t (3)

Control of setting the required duty cycle of the signal U, (t) and compensation of the first harmonics of the signals U, (t) and U {t) is performed by vanishing the second and first harmonics of the signal U, (t), respectively, on the screen of the analyzer 6 55

Next, the signal U (t) through the voltage divider 4, which attenuates the signal K times, is fed to the first input of the adder 5, the second input of the adder receives a signal from the generator 1

U (t) and sin lO t 4 / P and sincJt (4)

At the output of the adder, a signal appears with a calibrated harmonic factor equal to

 sk4

and

100%

(five)

where Vfn.j is the root mean square value of the signal voltage or higher harmonics of the generated signal at the output of the adder 5; Uc is the rms value of the signal voltage or the first harmonic of the generated signal at the output of the adder 5. Substituting the rms value of the signal voltages (3) and (4) into the expression (5), get

mc - € iL: ii ± jlllUil 4 / (2-i, K

.. | i) -.

100%

(6)

to

100%

From expression (6) it can be seen that the required K generated signal can be set with a precision divider 4 voltage, which can be calibrated in advance in terms of K,

Claims (1)

Formula image shadow A device for generating a signal with a given harmonic coefficient containing a sinusoidal signal generator, the output of which is connected to the input of the first adder, to the second input of which a voltage divider is connected, characterized in that, in order to improve the accuracy of setting the harmonic coefficient, a series-connected pulse generator is introduced, the second an adder and a spectrum analyzer, with the synchronization input of the pulse generator and the second input of the second adder connected to the generator output a sinusoidal signal And the second adder output is connected to the input of the voltage divider. -