JPS6083413A - Variable phase device - Google Patents

Abstract

PURPOSE:To obtain a signal which has small variation in amplitude and shifts in phase over a wide range by adding the in-phase component of a phase wave signal to a signal obtained by adding the opposite-phase component of an input signal and the in-phase component of the phase wave signal together. CONSTITUTION:The 1st differential amplifier 17 calculates the difference between the bias voltage of a power source 28 and the phase wave signal Sl supplied from a phase device 15 to the base side of a transistor (TR) 22. The phase wave signal Sl is supplied to the base side of a TR23 of the 2nd differential amplifier 18 and the AC input signal Sm is supplied to the base side of a TR24, so the output of the operational amplifier 18 is the composite signal of the in- phase component of the phase wave signal Sl and the opposite-phase component of the input signal Sm. In this case, said signal obtained by the addition and the output of the operational amplifier 17, i.e. in-phase component of the phase wave signal Sl are supplied to a common resistance 25, so they are added together here and the addition result appears at an output terminal 27 as an output signal SO.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention uses a variable phase device, particularly a differential amplifier, to suppress changes in the amplitude of an output signal and to widen the range in which the phase of the output signal changes. This invention relates to a variable phase device.

[Prior art]

Conventionally, a variable phase shifter consists of a variable resistor 2 and a capacitor 3 connected in series between a terminal l to which an AC input signal is supplied and the ground, as shown in FIG. Connect the connection point to output terminal 4, and connect this terminal 4 to output terminal 4.
An output signal whose phase is adjusted by a desired value is obtained.

In this case, the magnitude of the phase θ of the output signal with respect to the input signal is given by the following equation.

θ=jan (-wcR) However, U is each frequency of the input signal, C is the capacitance of the capacitor 3, and R is the resistance value of the resistor 2.

Therefore, by adjusting the magnitude of the resistor 2, the magnitude of the phase θ can be changed.

However, when using a variable phase shifter with such a configuration, when the value of the phase θ is changed, the amplitude of the output signal also changes depending on the capacitance C2 of the capacitor and the resistance value R of the resistor 2. It had drawbacks. It also has the disadvantage that the phase can only be changed within a range of 0 to 90 degrees.

[Summary of the invention]

An object of the present invention has been made to eliminate the above-mentioned drawbacks, and uses a differential amplifier to process an AC input signal and a phase wave signal obtained by changing the phase of this input signal using a phase shifter. By adding the negative phase component of the input signal and the positive phase component of the phase wave signal, and further adding the positive phase component of the phase wave signal to the signal obtained by this addition, this addition result can be obtained. This will be explained in detail below using examples.

[Embodiments of the invention]

FIG. 2 is a circuit diagram showing an embodiment of the variable phase device according to the present invention. A phase shifter 15 consisting of a series circuit of a variable resistor 13 and a capacitor 14 is connected to the connected wiring 12, and a phase wave signal SX is output from a connection point 16 between the resistor 13 and the capacitor 14 of this phase shifter 15. . 17 is the first
The differential amplifier 18 is a second differential amplifier. The first operational amplifier 17 consists of a pair of transistors 21 and 22 whose emitter sides are connected to each other via emitter resistors 191 and 192 and then grounded via a constant current source 201. The second differential amplifier 18 has an emitter resistor 193.
It is composed of a pair of transistors 23 and 24 that are connected to each other via a constant current source 202 and then grounded via a constant current source 202. The collector sides of the transistors 21 and 24 are connected in common, and then connected to the positive side of a DC power supply 26 via a load resistor 25.
The collector sides of are connected in common and then connected to the positive electrode side of the power supply 26. The negative electrode side of the power source 26 is grounded. A connection point between the load resistor 25 and the collector side of the transistor 21.24 is connected to an output terminal 27, from which an output signal SO is obtained. The base of the transistor 21 is connected to the positive side of a DC power source 28, and the positive side of the power source 28 is connected to the wiring 1 through a bias resistor 29.
Connected to 2. Therefore, a DC bias is applied to the base of the transistor 21, a DC bias is applied to the base side of the transistor 24 via the bias resistor 29, and furthermore, a DC bias is applied to the base side of the transistor 22, 23 via the bias resistor 29. A bias voltage is applied via variable resistor 13.

According to the above configuration, the first differential amplifier 17 calculates the difference between the bias voltage of the power supply 28 and the phase wave signal Sl from the phase shifter 15 supplied to the base side of the transistor 22. At this time, the collector side of the transistor 22 is connected to the resistor 25.
The phase wave signal SX supplied to the base of this transistor 22 appears as a positive phase component. Also, the transistor 2 of the second differential amplifier 18
Since the phase wave signal Sβ is supplied to the base side of the transistor 3 and the AC input signal Sm is supplied to the base side of the transistor 24, the output of the second differential amplifier 18 is the phase wave signal Sβ.
The signal is the sum of the positive phase component of g and the negative phase component of the input signal Sm. Note that the collector of the transistor 23 is connected to the high potential side of the resistor 25, and a positive phase component appears, and the transistor 24
The collector of is connected to the low potential side of the resistor 25, and an antiphase bone appears. In this case, the signal of this addition result (signal P to be described later)
) and the output of the first differential amplifier 17, that is, the positive phase component of the phase wave signal SZ, are supplied to the common load resistor 25, so they are added here, and this addition result is output from the output terminal 27. Supplied as signal SO.

FIG. 3 (al to fdl are diagrams showing the operation of the variable phase device described above, in which the input signal Sm, the phase signal s7!, the output signal SO, and the output signal P of the second differential amplifier are expressed using vectors. As is clear from the figure, by adding the negative phase component of the input signal Sm and the positive phase component of the phase wave signal Sll by the second differential amplifier 18, a vector shown as P is obtained. In addition, the positive phase component of the phase wave signal Sβ is output from the first differential amplifier 17, and a signal obtained by adding this signal and the above signal P is obtained from the output terminal 27 as the output signal SO. Here, when the resistance value of the resistor 13 is changed from 0 to infinity, each signal changes as shown in FIG. 3 fa) to (dl), and the output signal S
As the resistance value of the resistor 13 increases, the phase angle θ of O changes from 0 to approximately 180°, and its amplitude (vector length) hardly changes. The following methods can suppress changes in amplitude. If the signal from the second amplifier 18 is simply used as the output signal, a large change in phase can be obtained to some extent, but as is clear from FIG. 3, the amplitude will change. Therefore, this is compensated for by adding the positive phase component of the phase wave signal Sβ output from the first operational amplifier 17 to the output signal of the second operational amplifier 18.

In this embodiment, the phase shifter 15 has been described as changing the resistance value of the resistor 13, but the phase shifter 15 may change the capacitance of the capacitor 14.

Also, 1st. The second differential amplifiers 17 and 18 do not need to be constructed from bipolar transistors (they may be constructed from other amplification elements such as FETs).

Further, as the DC power source 28, a voltage obtained by dividing the voltage of the power source 26 may be used.

〔Effect of the invention〕

As explained above, according to the variable phase device according to the present invention, it is possible to suppress changes in the amplitude of the output signal and to change the phase angle of the output signal over a wide range. Further, the gain can be stabilized based on the first differential amplifier.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional variable phase shifter. 10...Input terminal, 13...Variable resistor, 14...
Capacitor, 15... Phase shifter, 17... First differential amplifier, 1B... Second differential amplifier, 21-24... Transistor, 27... Output terminal. Agent Masuo Oiwa (2 idiots) Procedural amendment document Showa Ta/Getsu/Z date 2, name of the invention variable phase device 3, person making the amendment 5, description of the specification to be amended "Detailed description of the invention" column. Contents of the 66 Amendment (1) In the 11th line of page 3 of the specification, the phrase "not much" is amended to read "few." (2) In the 11th and 12th lines of page 5 of the specification, "the collector side of the transistor 22 is connected to..." is corrected to "to the output terminal 27." (3) From page 5, line 20 to page 6, line 4 of the specification “
Note that the collector 1 of the transistor 23 appears with an opposite phase. ” will be deleted. (4) In the seventh and eighth lines of the specification, the statement ``In addition, the gain can be stabilized based on the first differential amplifier.'' is deleted. 2

Claims (1)

[Claims] (11 A phase shifter to which an AC input signal is supplied, a phase wave signal outputted from this phase shifter is supplied to one input terminal, and a DC bias is supplied to the other input terminal, and the phase wave signal output from the phase shifter is supplied to one input terminal. a first differential amplifier that outputs a positive phase component, the input signal is supplied to one input terminal, the phase wave signal is supplied to the other input terminal, and a negative phase component of the input signal and the phase wave signal are supplied; and a second differential amplifier that outputs the sum of the positive phase component of the differential amplifier, and outputs a signal obtained by adding the output of the first differential amplifier and the output of the second differential amplifier. A variable phase device featuring: