JPH10242761A - Differential transformer exciting oscillation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely output the sine wave frequency requested at the primary side of an exciting coil of a differential transformer and also to prevent the deterioration of characteristic due to the temperature drift, etc., by securing the connection among a crystal oscillator, a frequency dividing circuit, a waveform conversion circuit and a voltage control circuit respectively. SOLUTION: A crystal oscillator 1 oscillates the highly precise voltage of a fixed level and a square waveform of a fixed frequency level. A frequency dividing circuit 3 divides the frequency f1 of the square waveform which is outputted from the oscillator 1 into the sine wave frequency f2 that is requested at the primary side of an exciting coil of a differential transformer 2. The waveform conversion circuit 4 converts the square waveform of voltage 0V-A1 V and frequency f2 that is outputted from the circuit 3 into a sine wave shown by A2 sin2πf2 t. Then a voltage control circuit 5 controls the voltage A2 V of the sine wave outputted from the circuit 4 to the voltage A3 V of the sine wave that is requested at the primary side of the exciting coil of the transformer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator for exciting a differential transformer using a crystal oscillator.

[0002]

2. Description of the Related Art FIG. 4 shows, for example, Japanese Patent Publication No. 61-13638.
FIG. 1 is a configuration diagram showing a conventional differential transformer excitation oscillating device disclosed in Japanese Unexamined Patent Publication (Kokai) Publication. In the figure, a sine-wave oscillator 11 converts a volume resistor 13 to a voltage required on the primary side of an exciting coil in a differential transformer 12 and a frequency required by a primary side of the exciting coil in a differential transformer 12. The volume resistor 14 is connected.

Next, the operation will be described. The sine wave oscillator 11 generates a sine wave close to the sine wave required on the primary side of the exciting coil in the differential transformer 12. Next, the differential transformer 12 is controlled by the volume resistors 13 and 14.
Is adjusted to a sine wave having a voltage and a frequency required on the primary side of the exciting coil.

[0004]

Since the conventional oscillator for differential transformer excitation is constructed as described above, it is composed of a pure analog circuit, for example, a quadrature oscillation circuit.
There is a problem that voltage adjustment and the like are required, and characteristics are deteriorated due to temperature drift and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can accurately output the frequency of a sine wave required on the primary side of an exciting coil in a differential transformer, as well as temperature drift and the like. Accordingly, an object of the present invention is to obtain an oscillator for exciting a differential transformer which does not cause deterioration of characteristics.

[0006]

An oscillator for exciting a differential transformer according to the present invention includes a crystal oscillator for generating a rectangular wave, and a frequency of the rectangular wave oscillated by the crystal oscillator is set on the primary side of a differential transformer excitation coil. A frequency conversion circuit that converts the frequency of the signal to the frequency required by the frequency conversion circuit, a waveform conversion circuit that converts a rectangular wave output by the frequency conversion circuit into a sine wave, and a differential transformer excitation coil that converts the voltage of the signal output from the waveform conversion circuit. It is configured by connecting to a voltage adjusting circuit for converting the voltage required on the primary side.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a crystal oscillator 1 that oscillates a rectangular wave has a frequency of an output signal from the crystal oscillator 1 and a primary side of an exciting coil in a differential transformer 2. A frequency dividing circuit 3 for converting the signal into a sine wave frequency required by the following equation, a waveform converting circuit 4 for converting a square wave signal output from the frequency dividing circuit 3 into a sine wave signal, and an output signal from the waveform converting circuit 4 Are respectively connected to voltage regulation circuits 5 that convert the voltage of the differential transformer 2 into a sine wave voltage required on the primary side of the exciting coil in the differential transformer 2.

Next, the operation will be described. Crystal oscillator 1
As a result, a square wave having a highly accurate constant voltage and constant frequency is oscillated. Next, the frequency dividing circuit 3 changes the frequency f ₁ of the square wave output from the crystal oscillator 1 to a frequency f ₂ of a sine wave required on the primary side of the exciting coil in the differential transformer 2 as shown in FIG. Divide. Further, the waveform conversion circuit 4 converts the square wave having the voltage 0V-A ₁ V and the frequency f ₂ output from the frequency dividing circuit 3 into a sine wave represented by A ₂ sin2πf ₂ t as shown in FIG. I do. Next, the voltage adjustment circuit 5 adjusts the sine wave voltage A ₂ V output by the waveform conversion circuit 4 to the sine wave voltage A ₃ V required on the primary side of the exciting coil in the differential transformer 2. The voltage adjusting circuit 5 in the present embodiment is configured by, for example, a multiplying D / A converter, and is configured by inputting α satisfying A ₂ × α = A ₃ from another circuit to the multiplying D / A converter.

[0009]

According to the oscillator for exciting a differential transformer according to the present invention, the crystal oscillator for generating a rectangular wave and the frequency of the rectangular wave oscillated by the crystal oscillator are required on the primary side of the differential transformer exciting coil. Frequency conversion circuit, a frequency conversion circuit for converting a rectangular wave output from the frequency conversion circuit into a sine wave, and a voltage of a signal output from the waveform conversion circuit for the primary coil of the differential transformer. Since it is configured by connecting to a voltage adjustment circuit that converts to the voltage required on the side,
By obtaining the oscillation frequency by the crystal oscillator, a high-precision oscillator can be obtained, and furthermore, it is possible to obtain an oscillator for exciting a differential transformer in which characteristics do not deteriorate due to temperature drift or the like.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an oscillator for exciting a differential transformer according to the present invention.

FIG. 2 is a diagram showing characteristics of a frequency dividing circuit in the oscillator for exciting a differential transformer according to the present invention.

FIG. 3 is a diagram illustrating characteristics of a waveform conversion circuit in the oscillator for exciting a differential transformer according to the present invention.

FIG. 4 is a configuration diagram showing a conventional oscillator for exciting a differential transformer.

[Description of Signs] 1 crystal oscillator, 2 differential transformer, 3 divider circuit, 4
Waveform conversion circuit, 5 voltage adjustment circuit.

Claims (1)

[Claims] 1. A crystal oscillator for generating a rectangular wave, a frequency dividing circuit for converting the frequency of the rectangular wave oscillated by the crystal oscillator to a frequency required on the primary side of a differential transformer excitation coil, and the frequency dividing circuit And a voltage conversion circuit for converting the voltage of the signal output from the waveform conversion circuit into a voltage required on the primary side of the differential transformer excitation coil. An oscillator for exciting a differential transformer.