JPH03210490A - Azimuth display apparatus - Google Patents

Abstract

PURPOSE:To simplify the adjustment at the time of installation by reading amplitude modulated pulse data partitioned by data showing zero voltage to convert the same to analogue data by a D/A converter and applying this D/A conversion output to a DC obstructing means to obtain an equilibrium modulation signal. CONSTITUTION:Sine wave amplitude modulated pulse data and cosine wave amplitude modulated pulse data partitioned by zero data are read from memory devices 11A, 11B and converted to analogue data by a D/A converter to obtain amplitude modulated pulses Pa, Pb which are, in turn, applied to DC obstructing means 10A, 10B to obtain DC obstructing equilibrium modulation signals Sa, Sb. Therefore, only by adjusting the reading start timings of the memory devices 11A, 11B, the rotary phase of an antenna 1 and the phase relation between two phase equilibrium modulation signals Sa, Sb can be adjusted.

Description

[Detailed description of the invention] "Industrial application field" The present invention relates to an orientation display device used in ships and the like.

"Prior Art" A conventional direction display device connects a low-frequency goniometer to the rotation axis of a high-frequency goniometer for rotating the pointing direction of an antenna and obtaining a high-frequency received signal modulated by the direction component. low frequency signal (30KH
z) to create two balanced modulation signals with a phase difference of 90 degrees in amplitude that are synchronized with the rotation of the pointing direction of the antenna, and convert these two balanced modulation signals into the level of the received signal obtained from the high frequency goniometer Either obtain a signal that is amplitude modulated according to the received signal level, or give a signal that modulates a low frequency signal at the received signal level to a low frequency goniometer to obtain two balanced modulated signals with a phase difference of 90°, and then Two balanced modulation signals are applied to the X-axis and Y-axis of a cathode ray tube display, and a propeller-shaped image is displayed to indicate the direction of arrival of radio waves.

"Problems to be Solved by the Invention" According to the conventional structure, (1) a mechanical structure is required to rotate the low frequency goniometer in synchronization with the high frequency goniometer. ■It is necessary to adjust the electrical phase matching between the high-frequency goniometer and the low-frequency goniometer by mechanical positioning, and this adjustment takes a lot of effort.■There are restrictions on the location of the low-frequency goniometer. There are drawbacks.

The present invention uses an electronic circuit configuration that is relatively small and has a structure that can generate a balanced modulation signal independently of the high-frequency goniometer, and eliminates restrictions on placement and electrical phase matching. The present invention provides an orientation display device that can eliminate the trouble of adjustment.

In this invention, the amplitude data of sine waves and cosine waves are stored in a memory device, and this memory device is read out in synchronization with the rotation of the antenna, that is, the rotation of the goniometer, and two balanced modulations having the amplitude phases of the sine wave and cosine wave are generated. It is configured to obtain signals.

In particular, the amplitude data stored in the memory is amplitude modulated pulse data separated by data representing zero voltage, and this amplitude modulated pulse data is successively output and DA converted,
By applying this DA conversion output to the DC blocking means, a balanced modulation signal can be obtained from the DC blocking means. As a result, the present invention provides an azimuth display device which has a simple structure and can adjust the phase of the azimuth component and the two-phase balanced modulation signal by electronic means, and therefore can be easily adjusted during installation. can.

"Example" In the first part, an example of the present invention will be shown. In the figure, 1 is a pair of antennas with directivity, 2 is a high frequency goniometer that extracts the azimuth component from the antenna 1, and 3 is a motor that rotates the moving coil of the goniometer 2. 4 indicates a rotary encoder.

The rotary encoder 4 rotates together with the high-frequency goniometer 2, and outputs one pulse CK, 0, and 0 per rotation.
．． It is assumed that one pulse CK z is output every 2 degrees. 5 is a sense determination antenna, 6A and 6B are sense switches, 7 is a receiver, and 8 is a detector. Detection by the detector 8 is, for example, negative polarity detection, and the negative polarity detection output is supplied to the direction display device 9.

The direction display device 9 according to the present invention includes a pair of memory devices 11A,
IIB, an address counter 12 that provides address signals to the memories 11A and 11B, and memories 11A and 11B.
DA converters 13A and 13B convert digital data read from the DA converters 13A and 13B, and
Amplifier 14A, 1 that amplifies the A conversion output to a predetermined level
4B, the DC blocking means 10A, the IOB, and the resonator 1 excited by the output signals of the DC blocking means 10A and 10B.
5A, 15B and the output signals of resonators 15A, 15B are
A sense determination circuit 1 which applies a brightness modulation signal to the cathode ray tube display 16 applied to the axis input terminal and the X-axis input terminal, and the brightness modulation terminal G of the cathode ray tube display 16 to determine the direction of arrival of radio waves.
7.

The present invention is characterized in that amplitude-modulated pulse data having sine wave-like amplitude data and cosine-wave-like amplitude data is stored in a pair of memories 11A and 11B.

FIGS. 2A and 2B show the signal waveforms read from the pair of memories 11A and IIB and subjected to DA conversion. The amplitude modulation pulses Pa and Pb shown in FIG. 2A and FIG. 2A are arranged so that the envelopes of their peak values are in the shape of a sine wave and a cosine wave, and data for one cycle is written in the memories IA and IB as a whole. The amplitude modulation pulses Pa and Pb each have their phases reversed in the first half cycle and the second half cycle in one cycle. The amplitude modulated pulses Pa and Pb are applied to the DC blocking means 10A and ROB, and by removing the DC component contained in the amplitude modulated pulses Pa and pb, the carrier wave is So-called balanced modulation signals Sa and sb whose phases are reversed
is obtained.

Memory device 11. For example, a semiconductor memory such as a ROM can be used for A and IIB. As for the resolution of the write data, for example, amplitude data changed by 0.2 degrees is written alternately with zero data for each address. Further, the resolution in the amplitude direction is quantized to, for example, 255 steps.

The memories 11A and IIB are supplied with count output signals from the address counter 12, and are repeatedly read from the first address to the last address. The pulses CK output from the rotary encoder 4 with a resolution of 0 and 2 degrees are given to the address counter 12 so that this successive period coincides with the rotation period of the high-frequency goniometer 2, and the counted output is stored as an address signal. The address counter 12 is reset by the pulse CK which is applied to the goniometers 11A and IIB and generated every time the goniometer 2 rotates once, and the goniometer 20 rotates and the memory 11A.

The relationship between the successive cycles of 11B is always made to match. Reference numeral 18 denotes a synchronization circuit, and the synchronization circuit 18 is used to match the timing at which the counter 12 is reset and the timing at which the goniometer 2 passes the reference point.

Here, a phase adjustment means 21 is provided between the rotary encoder 4 and the synchronization circuit 18. This phase adjustment means 21
For example, the preset counter 21A can be configured by a phase setter 21B that provides a set value to the preset counter 21A. The phase setter 21B can be configured by, for example, a digital switch.

The preset counter 21A can be either an up counter or a down counter.

For example, a case where a down counter is used will be explained.

Set a value corresponding to the delay angle in the phase setter 21B,
The set value is synchronized pulse CK.

It is sufficient to preset the preset counter 21A with the pulse CK, and then count down the preset value with the pulse CK. For example, to delay the synchronization pulse CK by 1°, set 110.2=5, that is, a digital value equivalent to "5" in decimal notation in the phase setter 21B, and apply this setting value at the timing of the synchronization pulse CK +. Preset the preset counter 21A and apply the preset value to the pulse CK.
When five pulses CK, are inputted by down-counting with i, a down-down signal CK,' is obtained from the preset counter 21A.

Therefore, by applying the downshift signals CK,' to the reset terminal R of the address counter 12 through the synchronization circuit 18, the rotational phase of the antenna 1 can be adjusted to the memory 11A, II.
It is possible to delay the phase of the start point of B by 1°. Therefore, by setting an arbitrary value to the phase setter 21B, the phase of the azimuth component and the phase of the two-phase balanced modulation signal generated from the memory devices 11A and IIB can be adjusted to an arbitrary relationship. As a result, the azimuth component obtained from the antenna l is transmitted to the receiver 7. The structure is such that the reference point of the azimuth component and the phase of the two-phase balanced modulation signal can be electronically adjusted even if it is delayed by the detector 8 or the like.

Amplitude modulated pulse data having sine amplitude data and amplitude modulated pulse data having cosine amplitude data read from the memories 11A and IIB are applied to DA converters 13A and 13B for DA conversion. Through this DA conversion, amplitude modulated pulses Pa and Pb shown in FIG. 2A and FIG. 2 are obtained.

These amplitude modulated pulses Pa and Pb are applied to the amplifier 1 as necessary.
4A and 14B to a predetermined level, and supplies it to the DC blocking means 10A and IOB.

The direct current blocking means 10A and IOB can be constituted by capacitors. By applying amplitude modulation pulses Pa and Pb to the DC blocking means 10A and 10B, balanced modulation signals Sa and Sb shown in FIG. 2C and D are obtained. The balanced modulation signals Sa and sb are applied to the resonators 15A and 15B to generate the balanced modulation signal Sa.

The waveform of the carrier component of sb is shaped into a sine wave and is applied to each of the X-axis and Y-axis input terminals of the cathode ray tube display 16.

On the other hand, a constant DC bias voltage -E is applied from the operational amplifier 18 to the reference voltage terminal REF of the DA converters 13A and 13B, and a detector 8 is applied to the other input terminal of the operational amplifier 19.
The detected output signal is superimposed on the DC bias voltage, and this superimposed signal is sent to the DA converters 13A and 13B.
is applied to the reference voltage terminal REF.

Reference numeral 17 indicates a sense determining circuit. This sense determination circuit 17
By turning on the sense decision switches 6A and 6B, the game controller 17B is controlled to open and becomes operational. That is, the signal received by the sense antenna 5 is added to the azimuth component extracted by the goniometer 2, and the gate 17B is controlled to be open, and a brightness modulation signal is applied to the brightness modulation terminal C of the cathode ray tube display 16 through this gate 17B. As this brightness modulation signal, for example, the least significant bit signal of the address signal for reading out the memories 11A and 11B can be used. The signal of the least significant bit of the address signal is a balanced modulation signal Sa,
The frequency matches the frequency of the carrier component of Sb, and this brightness modulation signal is transmitted to the brightness modulation terminal G of the cathode ray tube display 16 through the amplifier 17C1, the DC blocking means 17D, and the resonator 17E.
By applying this signal to the anti-1 signal, the components of one polarity among the signal components received by the anti-1 are erased, and only the image displayed by the component of one polarity is displayed. At this time, the image changes from a propeller shape to a cardioid shape, and the direction of arrival of the radio waves is determined by the direction of the cardioid. 17F is a polarity setting circuit that sets the polarity of the brightness modulation signal for sense determination. The polarity of the brightness modulation signal is selected by the signal applied to the input terminal 17A of the polarity setting circuit 17F. This selection of polarity is determined in advance by the arrangement of the receiving antenna 1 and the sense antenna 5, and once it is determined at the time of installation, it cannot be changed thereafter.

"Operation" According to the configuration of the present invention described above, the memory devices 11A and IIB
Since amplitude data of sine wave and cosine wave amplitude modulated pulses are read out alternately together with data of zero amplitude value, the DA converters 13A and 13B output amplitude modulation in a sine wave shape, as shown in FIGS. 2A and 2B. It is possible to obtain an amplitude modulated pulse Pa whose amplitude is modulated and an amplitude modulated pulse Pb whose amplitude is modulated in the form of a cosine wave.

When there is no received signal, the DA from the operational amplifier 19
Since a constant bias voltage -E3 is applied to each group IIS voltage terminal REF of the converters 13A and 13B, D
The amplitude modulated pulses Pa and Pb output from the A converters 13A and 13B have sine wave and cosine wave amplitudes synchronized with the rotation of the goniometer 2. (Third diagram, time T0~
By applying these amplitude modulated pulses Pa and pb to the DC blocking means IOA and IOB, a balanced modulated signal Sa is generated.
(Fig. 3E) and a balanced modulation signal Sb (Fig. 3G) can be obtained. Therefore, the balanced modulation signals Sa and S+) are passed through the resonators 15A and 15B to the
As shown in FIG. 4, a circle with a radius determined by the bias voltage -E6 is drawn on the tube surface of the cathode ray tube display 11 by applying it to the bias voltage -E6. If the resonators 15A and 15B are not provided, the carrier signals of the two-phase balanced modulation signals Sa and Sb will be rectangular waveforms and will be given to the X and Y axes, so the electron beam will be deflected from one side to the other. Because the speed is so fast, a circle is drawn whose inside does not shine at all. When such a display method is adopted, the resonators 15A and 15B are not required.

On the other hand, for example, if a radio wave arrives from a direction deviated by 90 degrees from the ship's course direction, the detected output signal of the detector 8 will be the third
A waveform as shown at time T1 to T2 in FIG. B is obtained. By applying this detection output signal to the operational amplifier 19, the output of the operational amplifier 19 is at the time T + "" T shown in FIG. 3C.
As shown in x, a signal is obtained in which the detection output signal is superimposed on the bias voltage -E. By applying this superimposed signal to the base f$ voltage terminal REF of the DA converters 13A and 13B, the amplitude is modulated from the DA converters 13A and 13B to the amplitudes shown at times T and -T in the third diagram and F. Amplitude modulated pulses Pa', Pb' are obtained. This amplitude modulated pulse P
By supplying a' and Pb' to the resonators 15A and 15B, balanced modulation signals Sa' and Sb' shown in FIGS. 3E and G are obtained from the resonators 15A and 15B. These balanced modulation signals Sa' and Sb' are connected to the X-axis and Y-axis of the cathode ray tube display 16.
By applying it to the shaft, a propeller-shaped image as shown in FIG. 5 appears. As usual, a sense signal is added to this propeller-shaped image to determine the direction of arrival of the radio waves.

"Effect" As explained above, according to the present invention, the memory devices IIA and I
Amplitude modulated pulse data in the form of a sine wave and amplitude modulated pulse data in the form of a cosine wave separated by zero data are read from the IB, and the pulse data is subjected to DA conversion to obtain amplitude modulated pulses Pa and Pb.
Since the structure is such that balanced modulation signals Sa and Sb are obtained by applying a and pb to the DC blocking means 10A and IOB, the rotational phase of the antenna 1 and the two-phase balance can be achieved by simply adjusting the timing at which the memory units 11A and IIB start successive outputs. Modulation signals Sa, S
The phase relationship of b can be adjusted.

This adjustment can be performed, for example, by the phase adjustment means 21, and by setting an arbitrary value in the phase setter 21B, the rotational phase of the antenna 1 and the two-phase balanced modulation signals Sa, Sb are adjusted.
The phase of can be easily adjusted.

In other words, even if a phase rotation is applied to the azimuth component signal in the receiver 7, the detector 8, etc., the phase adjustment means 21 can correct a phase shift corresponding to the amount of phase rotation. As a result, there is an advantage that the effort required during installation can be significantly reduced. Further, although an azimuth error may occur depending on the installation condition of the antenna l, this azimuth error can also be corrected by the phase adjustment means 21, and the structure is such that adjustment can be easily performed in this respect as well.

In addition, since the amplitude modulation pulse data separated by zero data is stored in the memory devices 11A and IIB, the balanced modulation signal Sa can be generated by simply reading out this amplitude modulation pulse data and applying its DA conversion output to the DC blocking means 10A, IOB. , S
Since b can be obtained, the circuit structure can be simplified.

In other words, the amplitude data of sine waves and cosine waves are stored in the memories 11A and 11B, and this amplitude data is read out to generate a balanced modulation signal whose amplitude changes in a sine wave pattern and a balanced modulation signal whose amplitude changes in a cosine wave pattern. There are several ways to obtain this, but such a method has the disadvantage that two double-balanced modulators are required, which increases the complexity of the circuit structure.

On the other hand, in the present invention, since the DC blocking means 10A10B can convert the signal into a balanced modulation signal, the circuit structure can be greatly simplified compared to the case where a double balanced modulator is used.

"Modified Embodiment" In the above description, the case where unipolar amplitude modulation pulse data is stored in the memories 11A and 11B has been described, but as shown in the sixth section, the balanced modulation signal Sa, which swings positively and negatively around zero, S
b itself can also be stored in the storage device 11A11B. In this case, a balanced modulation signal can be obtained directly from the DA converters 13A and 13B, and the direct current blocking means 10A,
Does not require IOB. However, DA converters 13A, 13
B requires a bipolar DA converter that can DA convert positive and negative digital signals.

As another example, as shown in FIG. 7, it may be configured to store amplitude modulated pulse data having, for example, a positive polarity DC component EDC. In the case of FIG. 7, the DA converters 13A and 13B may have the function of DA converting a unipolar digital signal.

In this case, the DA conversion output is transferred to the DC blocking means lOA.
By taking out the signals through the IOB, balanced modulation signals Sa and Sb shown in FIG. 2C and D can be obtained.

[Brief explanation of drawings]

FIG. 1 is a system diagram for explaining an embodiment of the present invention.
Fig. 2 is a waveform diagram for explaining the operation of the main part of this invention, Fig. 3 is a waveform diagram for explaining the operation of the entire azimuth display device according to the invention, and Figs. 4 and 5 are azimuth display. A front view for explaining examples of display results in the apparatus, and FIGS. 6 and 7 are waveform diagrams for explaining modified embodiments of the present invention. 1: Receiving antenna, 2: Goniometer, 3: Motor, 4
: drive circuit, 5: sense antenna, 6A, 6B: sense switch, 7: receiver, 8: detector, 9: direction display device, IIA, IIB: memory, 12 near address counter,
13A13B: DA converter, 14A, 14B: amplifier,
15A, 15B: Resonator, 16: Cathode ray tube display, 17
: sense determination circuit, 18: synchronization circuit, 19: operational amplifier, 21: phase adjustment means, 21A; preset counter,
21B: Phase setter, Pa: Amplitude modulation pulse with sinusoidal amplitude, Pb: Amplitude modulation pulse with cosine wave amplitude, Sa: Balanced modulation signal with sinusoidal amplitude, Sb Two cosine wave amplitude Balanced modulation signal with.

Claims (1)

[Claims] (1) A: A first memory storing amplitude modulated pulse data whose amplitude is modulated in a sine wave shape and whose phase is inverted every half cycle; B: Amplitude modulation whose amplitude is modulated in a cosine wave shape and whose phase is inverted every half cycle. a second memory storing pulse data; C. means for reading the first memory and the second memory in synchronization with the rotation of the pointing direction of the antenna; and D: the first memory and the second memory. a pair of DA converters that convert the amplitude modulated pulse data read from the device into amplitude modulated pulse signals; , F. A display device which displays the direction of arrival of radio waves by applying balanced modulation signals obtained from the amplitude modulation means to the X and Y axes, and an azimuth display device comprising: