SU756605A1 - Active phase filter - Google Patents

Description

The invention relates to radio engineering '.

The active phase circuit is known, containing an operational amplifier 5 (OU), whose non-inverting input is through a resistive voltage divider, and the inverting input is via a serial EC - circuit connected to the input of the phase circuit, and the midpoint of the CS Yu circuit is connected through the first capacitor to the output of the OU, and the first resistor connected by one output to the inverting input of the op-amp (1).

However, the sensitivity of the frequency characteristics to deviations of the parameters of the operational amplifier contained in the active phase circuit is high in the known active phase-15 circuit. 20

The purpose of the invention is to reduce the sensitivity of the frequency characteristics to the deviations of the parameters of the operational amplifier. _

For this purpose, in the active phase circuit - 25 containing an operational amplifier (op amp), the non-inverting input of which is through a resistive voltage divider, and the inverting input is connected via a serial PC circuit to 30

the input of the phase circuit, and the midpoint of the CS circuit is connected through the first capacitor to the output of an op-amp, and the first resistor connected by one output to the inverting input of the op-amp, the second output of the first resistor through the additionally input the second resistor and the second capacitor connected to the output 0У and the input of the phase circuit respectively, and a third resistor is connected in parallel with the first capacitor.

The drawing shows the principal electric circuit of the active phase circuit.

The active phase circuit contains an operational amplifier (OU) G, resistive (resistors) voltage divider 2.3, EC-circuit (resistor) 4, capacitor 5, capacitor 6, resistor 7, capacitor 8, resistors 9 and

ten.

The operation of the device is carried out using the transfer function.

-

756605

provided that

where £, &"£" with ₂ conductivity of the resistor ___ · ι ________

___ 'I ____

....... ι · _________

- ----. I ·.

capacitor capacitance

- ... "I .... ·

- “I.

four;

7;

9;

ten;

2;

3;

five;

6;

eight.

The calculated states for the parameters of the elements are as follows:

ί & ’β'ίβτΟ” ’” - 5, £, = *

The coefficient M characterizes the variation of the parameters of identical elements. Sensitivity of the transfer function

10 to the gain is estimated by the magnitude of the efficiency factor:

'Ί ^' Ι’Λ ρ, ^

п „ _т -2 _? about.

Technical and economic efficiency of the 20 phase circuit is to reduce the sensitivity of the frequency characteristics of the phase circuit to the deviations of the parameters of the operational amplifier, which it contains. 25

Claims (1)

Claim Active phase circuit containing an operational amplifier (op-amp), a non-inverting input of which is through a resistive voltage divider, and an inverting input is connected via a serial KS circuit to the input of the phase circuit, and the midpoint of the NSN circuit is connected through the first capacitor to the output 0У, and the first resistor connected by one output to the inverting input 0U, characterized in that, in order to reduce the sensitivity of the frequency characteristics of the phase circuit to the deviations of the parameters 0У, the second output of the first resistor is additionally introduced, the second resistor and the second capacitor are connected to the output of the 0U and the input of the phase circuit, respectively, and a third resistor connected in parallel with the first capacitor.