JPS6130203B2 - - Google Patents

Description

[Detailed Description of the Invention] Single-axis and double-axis bubble electrolytic level sensors are currently used in navigation systems, missile launch systems, fixed bases,
Widely used as a tool leveling method.
Such level sensors use a fluid, such as an electrolyte, to detect changes in level about one or two axes, depending on the type used. When connected in a suitable bridge circuit excited with an alternating current voltage, the output of this sensor is a voltage whose magnitude is proportional to the tilt angle and whose phase (0° to 180°) indicates the direction of tilt. do.

For example, heading reference method
In many navigation systems, such as the azimuth rate
It is common to multiply by a second component such as (AZ)). This multiplication is conventionally performed by separate electronic multipliers that require additional equipment and circuitry and are fairly expensive to increase accuracy. Electronic multiplier circuits must be calibrated and adjusted for proper operation and must be operated by an expert.

However, in the device of the invention, this multiplication is performed within the bubble level sensor itself, thus eliminating the need for a separate electronic multiplier. The device of the present invention is simpler and less expensive than conventional devices, does not have the errors inherent in electronic multipliers, and eliminates the need for multiplier adjustment.

As mentioned above, the present invention provides a simple device for performing two term multiplication using a bubble slope sensor or level sensor. Also, as mentioned above, this sensor is a device that generates an alternating current signal that is proportional to the declination (or inclination) of the sensor. If the output signal is the product of the sensor's declination and another external signal, the sensor according to the invention automatically causes its output to represent the product of the external signal and its declination. be made into This sensor therefore also acts as a multiplier, and this technique eliminates the need for an electronic multiplier in the device.

The block in FIG. 1 is an example of a prior art technique for multiplying the deflection angle of a bubble level sensor by an external signal.
This prior art has an electronic multiplier 10 for multiplying two independent DC signals. One DC signal is the external signal K _a , and the other is the AC output signal (Kφsin
ωt), and the latter is demodulated by the demodulator 14 and converted into direct current (Kφ). Demodulator 14 is a synchronous demodulator and is responsive to an AC excitation signal having the same frequency and constant amplitude as the AC excitation signal entering bubble level sensor 12.

The prior art system of FIG. 2 also uses an electronic multiplier 14 to illustrate how the same AC signal can be multiplied to produce an output signal that is the product of the two AC signals. The prior art device of FIG. 3, on the other hand, shows how the AC signal from the bubble level sensor is multiplied by an external DC signal in multiplier 14 to produce an output that is the product of the AC and DC signals. It is.

The bubble level sensor 12 has the property of obtaining a scale factor (AC volts/declination) that is proportional to its AC excitation signal. Thus, for a given AC excitation signal and a given deflection angle, an AC signal with a specific amplitude is generated. If this AC excitation signal is halved and has the same argument as above, then the amplitude of the AC output signal will also be halved.

Therefore, according to the present invention, as shown in FIG.
The bubble level sensor itself can be used as a multiplier by exciting the sensor with an AC external signal that is to be multiplied by the declination angle. The output of this sensor is automatically the product of this AC external signal and the declination angle.

In the configuration of _FIG .
_a sinωt).

The bubble level sensor is shown schematically and is adapted to be excited by a transformer _T1 . The secondary of transformer T ₁ has a center tap connected to ground, and the two secondary windings are adapted to provide push-pull signals to bubble level sensor 12 . If you think of the bubble level sensor as a pressure divider in this way,
In the absence of a slope, the circuit is balanced and the bubble sensor output is zero. When there is an inclination, the sensor output is determined by the angle of inclination and the DC input signal (Kφ・K _a cosω
t) and the equivalent alternating current. This output signal is amplified by an amplifier 24 and demodulated by a demodulator 26 to generate a DC output Kφ·K _a . Demodulator 2
6 is a synchronous demodulator, which uses the same reference signal applied to demodulator 20. However, the reference signal applied to demodulator 26 is shifted by 90° relative to the reference signal applied to modulator 20 to compensate for a similar shift in the signal through the circuitry associated with bubble level sensor 12. There is.

The circuit of FIG. 6 has an input terminal 50 which receives an AC reference signal (sin
ωt). Input terminal 50 is connected to the base of PNP transistor Q37 through resistor R146. The emitter of transistor Q37 is connected to the positive terminal of a 15 volt DC power supply, and the base is connected to this positive terminal through resistor R133. The collector of transistor Q37 is connected to the negative terminal of the power supply through resistor R134, and also connected to resistor R135.
and to the base of NPN transistor Q38 and the base of PNP transistor Q39.
Transistor Q37 is 2N2907A, Q38 is
2N2369A, Q38 may be 2N5910 type.

The emitters of transistors Q38 and Q39 are grounded. The collector of transistor Q38 is resistor R.
136 to the positive terminal of the 15 volt power supply and to its base through capacitor C46. The collector of transistor Q39 is connected to the negative terminal of this 15 volt supply through resistor R138 and to its base through capacitor C47. The collector of transistor Q38 is also connected to grounded resistor R137 and to the gate of field effect transistor Q40, and the collector of transistor Q39 is connected to grounded resistor R139 and the gate of field effect transistor Q41. Transistor Q40 is 2N3378, Q41 is
2N3824 type is fine. The DC input K _a (for example ÅZ) to be modulated by the AC reference signal is connected to input terminal 5.
2 into this circuit. Terminal 52 is connected to the drain electrode of transistor Q40 and the source electrode of transistor Q41 through resistor R147. The source of transistor Q40 is grounded and Q
The drain of 41 is connected to the negative input terminal of operational amplifier 54.

The positive input terminal of amplifier 54 is grounded, and its output is connected to the negative input terminal through resistor R142.
The operational amplifier 54 may be of the LM307 type. Amplifier 54
The output of resistors R143, R144 and R145
The latter is also connected to the positive input of the operational amplifier 56, which may also be of the LM307 type. Resistor R143 is also connected to a coupling capacitor C48, which is connected to the negative input and output of amplifier 56. The positive input of amplifier 56 is connected to grounded capacitor C.
49, the output of which is connected to the primary winding of the transformer _T1 through a capacitor C50. The other side of this transformer is grounded by a central tap.

Describing the operation of such a circuit, the level of the square wave input applied to the terminal 50 is controlled by the transistor Q.
37 and amplified by driver circuits associated with transistors Q38 and Q39 to drive transistors Q40 and Q4 in proper phase.
Added to 1. These field effect transistors act as switches to chop the DC input applied to terminal 52 at the frequency of the AC reference signal.
The resulting modulated alternating current signal is sent to operational amplifier 54.
and passes through the circuit of the operational amplifier 56 constituting the filter 22 to the coupling transformer T ₁ , whereby this modulated reference signal enters the bridge circuit of the bubble level sensor 12 .

Output of bubble level sensor (Kφ・K _a cosωt)
enters the positive input of amplifier 24 through coupling capacitor C28. This amplifier may be of type LM301A. The positive input terminal of this amplifier is a grounded resistor R
91, and its output terminal is connected to capacitor C33.
and field effect transistor Q3 via resistor R99.
0 and the drain electrode of field effect transistor Q29. These circuits are demodulator 2
6. Transistor Q29 is 2N3378,
Q30 can be 2N3824 type.

An alternating current reference signal (sinωt), or signal (cosωt), which is 90° out of phase, is applied to input terminal 56. Terminal 56 is connected to 2N2907A through resistor R88.
It is connected to the base of a PNP transistor Q26, which has a good shape. The circuit of transistor Q36 acts as a level shifter to interface the demodulator circuit with the incoming reference signal. The emitter of transistor Q26 is connected to the positive terminal of the 15 volt power supply, and the base is connected to that terminal through resistor R89. The collector of transistor Q26 is connected to the negative terminal of this power supply through resistor R93.

The collector of transistor Q26 is connected to a pair of driver transistors Q27 and Q2 through resistor R29.
Connect to the base of 8. Transistor Q27 is
The transistor Q28 is an NPN transistor, which may be 2N2369A, and transistor Q28 is a PNP transistor, which may be 2N5910. The collectors of transistors Q27 and Q28 are connected respectively to the positive terminal of the 15 volt power supply through resistor R95 and to the negative terminal through resistor R96.
Capacitor C51 is connected to the collector and base of transistor Q27, and capacitor C52 is connected to the collector and base of transistor Q28.

The collector of transistor Q27 is connected to the gate of transistor Q29 and a grounded resistor R97. The collector of transistor Q28 is connected to the gate of transistor Q30 and a grounded resistor R98. The DC outputs from these field effect transistors are applied to a DC amplifier 58, which may be an LM308A.
The output of this amplifier enters an output terminal 60, where a DC output Kφ·Ka (KφÅZ) is generated.

The invention therefore provides a simple and efficient device whereby the bubble level sensor can also act as a multiplier;
As a result, an output indicating the argument multiplied by the external factor can be obtained without using a separate multiplier.

[Brief explanation of the drawing]

1, 2, and 3 are block diagrams showing various conventional devices using separate multipliers, FIG. 4 is a block diagram showing the concept of the present invention, and FIG. 5 is a block diagram showing the concept of the present invention. The block diagram included in FIG. 6 is a circuit diagram of a device substantially the same as that in FIG. 10...multiplier, 12...bubble level sensor, 14...demodulator, 20...synchronous modulator,
22...filter, 24...amplifier, 26...demodulator.

Claims (1)

[Scope of Claims] 1. A bubble-type level sensor that responds to an alternating current excitation signal and generates an output having an amplitude proportional to the magnitude of the current and the deflection of the sensor from a reference level, and connected to the sensor. a first input circuit connected to the modulator and supplying the alternating current reference signal to the modulator; a first input circuit connected to the modulator and supplying the alternating current reference signal to the sensor; a second input circuit for supplying the modulator with a second DC input signal to be amplitude modulated based on the deviation of the sensor from the reference level and the amplitude of the second input signal; and an output circuit for extracting from the sensor an output signal having an amplitude representing the product of . 2. The argument measuring multiplier device according to claim 1, wherein the output circuit includes a demodulator for obtaining the output signal. 3. In the declination measurement multiplier device according to claim 1, the output signal is a DC signal having an amplitude representing the amplitude of the input signal multiplied by the declination of the sensor from the reference level. A deflection measurement multiplier device characterized by: 4. In the argument measuring multiplier device according to claim 2, the modulator and the demodulator are of a synchronous type, and the AC reference signal is applied to the modulator. An argument measuring multiplier device characterized by comprising a circuit that is synchronously introduced into the demodulator with a phase shift of 90°.