JPH0157750B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that uses a rotary encoder to rotate an electronic azimuth marker displayed on a display screen of a radar device that employs the PPI method.

Relatively new radar equipment replaces the traditional angularly graduated cursor board with an electronic orientation marker displayed on the display screen to measure the orientation of the signal present on the display screen. The turning of the azimuth marker to a desired azimuth is performed using a rotary encoder due to mechanical and cost considerations. That is, the rotary encoder is configured to add and subtract rotation pulses sent out every time the rotary encoder rotates by a certain angle based on the direction of rotation, and display the orientation marker at an angular position corresponding to the counted value. When observing signals in radar equipment, the rotary encoder has a azimuth resolution of 1
It is desirable to correspond to approximately 0.1° on the screen per rotational pulse. By the way, rotary encoders, which are currently popular, send out about 50 rotational pulses per rotation, so for example, if you want to turn the orientation marker half a circle on the screen, you have to rotate the rotary encoder 36 times. This makes it difficult to set up quickly, and also poses problems in practical terms. Therefore, as a method to achieve both the above-mentioned resolution and quick setting, (1) attaching a gear mechanism for increasing speed, or (2) using a high-resolution rotary encoder that sends out about 1000 rotational pulses per rotation, for example. It is possible to use

However, regarding (1), the addition of mechanical parts leads to an increase in the size of the device, and regarding (2), it is difficult to make fine adjustments due to the cost and conversely, so it cannot be said to be a fundamental solution.

The present invention has been made in view of the above, and uses a commonly used rotary encoder, and only when the rotation speed thereof is increased to a certain level or higher, the turning movement speed of the azimuth marker is made faster.
On the other hand, the present invention provides an orientation marker turning device using a rotary encoder that corresponds to the rotational speed during normal rotation.

The following description will be made based on the embodiments shown in the drawings.

In Fig. 1, 1 sends out, for example, 50 rotation pulses per rotation, and at the same time outputs a high (hereinafter referred to as H) level output when the rotation direction is clockwise, and a low (hereinafter referred to as H) level output when the rotation direction is counterclockwise. This is a rotary encoder that can detect the amount and direction of rotation by sending out a level output (referred to as L).
2 and 3 are operated by rotation pulses sent from the rotary encoder 1, and have fixed time widths t ₁ and t ₂
It is a monostable multi-pulse that sends out each pulse (<t ₁ ). The monostable multi ₂ and ₃
When the next rotational pulse is sent within, the operation continues for a certain period of time from that point onwards. 4 and 5 are D-types that determine whether the sending speed (period) of the rotation pulse is small, intermediate, or large compared to the times t ₁ and t ₂ and sends out 2 bits of information, 1 bit for each. It is a flip-flop (hereinafter referred to as FF). FF4 and 5 above are CK
When a rotation pulse is sent to the terminal, if the D terminal is at the H level, the Q output is maintained at the H level, and conversely, if the D terminal is at the L level, the L level is sent out. Reference numeral 6 denotes a selection gate that allows either a rotation pulse or a multiplication pulse to be described later to pass based on the output level of the FF 4.

7 to 10 are reversible counters; reversible counter 7
The output count value of reversible counter 8 is the value of the first digit after the decimal point, the output count value of reversible counter 9 is the value of the second digit, and the output of reversible counter 10 is the value of the second digit. The count value indicates the third digit, and from this it is possible to obtain an azimuth value of 0.0° to 359.9°. Although the range from 0.0° to 359.9° is not shown in the drawing, it is assumed that the range is continuous in terms of operation. The CI (carry-in) terminal of the reversible counter 7 is set to the L level state so that a counting operation is performed by sending a pulse passing through the selection gate 6 to the CK terminal. Conversely, reversible counters 8, 9, 1
The CI terminal is normally set to H level so that counting operations are prohibited except when carrying up or down for 0. Then, for carrying up or down by the reversible counters 8, 9, and 10, an L level signal is sent from each CO (carry out) terminal, and the counting operation of the reversible counters 8, 9, or 10 one digit higher is performed only once. This is done by Further, each U/D (up-down) terminal is configured to perform addition counting when an H level is applied, and subtractive counting when an L level is applied. The count values of the reversible counters 7 to 10 are sent, for example, in binary code and guided to the orientation display 11 and the orientation marker generation circuit 12.

Although the azimuth marker generating circuit 12 is not shown in detail in the figure, this circuit varies depending on the display method of the detection signal of the radar main body (not shown) including the display 13. In other words, (1) record the detection signal in one screen's worth of memory;
In the case of a system in which this is repeatedly read out and displayed by X-Y raster scanning or spiral scanning, in this case, the orientation θ is stored in the memory together with the detection signal, or is converted into the X, Y coordinates in a separate memory, or as it is ( (for spiral scanning)
is written at regular intervals. This certain period of time is related to the follow-up ability when changing direction, but it is conceivable to write to a predetermined location for each transmission (within a pause period from the end of writing the received signal to the next transmission), for example.
In addition, if a dedicated memory for the orientation θ is provided, it may be associated with the transmission, and an independent period (for example,
Writing may also be performed at the read/display cycle.

(2) In the case of a display method using radial scanning that rotates sequentially In this case, it is not necessary to memo the direction θ, but it is sufficient to import and display it at regular intervals. This fixed period of time is related to the tracking ability as described above, but may also be made to coincide with the transmission cycle, for example (scanning is performed at least once in the azimuth θ direction during the pause period from the end of displaying the received signal to the next transmission). , or about one integer fraction thereof.

In this way, the azimuth marker generation circuit 12 has a primary relationship with the display method, and although the outline of its operation has been explained in (1) and (2) above, such technology is well known.

Now, the rotation pulse from the rotary encoder 1 is also introduced into the phase comparator circuit 14. This circuit consisting of the phase comparison circuit 14, filter 15, voltage controlled oscillator (hereinafter referred to as VCO) 16, and frequency divider circuit 17 is a well-known multiplication PLL circuit. That is,
As an output, a pulse obtained by multiplying the rotation pulse by a reciprocal of the frequency division ratio of the frequency dividing circuit 17 is sent out. The frequency dividing circuit 17 has terminals "1" and "2" for setting the frequency dividing ratio.
The frequency dividing ratio is determined by adding the values of the terminals set to the H level state. Note that the terminal "1" is always in the H level state. for example,
When terminal "2" is set to H level, the frequency is divided by 3, and when terminal "4" is set to H level, it operates as a frequency divided by 7 circuit, and as a result, the output of VCO 16 is 3 times and 7 times the rotation pulse. A frequency multiplied pulse is obtained.

In the above circuit configuration, the second
This will be explained with reference to the waveform diagram in the figure.

In Figure 2, (a) is rotary encoder 1
is the normal speed (the rotational pulse sending period T is T>t ₁
(b) is a waveform diagram when the period T is in the range of t ₂ < T ≦ t ₁ ; (c)
is a waveform diagram when the period T is in the range of T≦t ₂ . For convenience of explanation, in each case, the current direction θ is
150.0°, and the rotation direction of rotary encoder 1 is clockwise.

Regarding case (A), the rotational pulse _A1 sent out from the rotary encoder 1 is guided to the monostable multiplexers 2 and 3 and the FFs 4 and 5. By sending the rotation pulse A ₁ mentioned above, the monostable multi 2 sends out an H level pulse B ₁ at time t ₁ ,
The monostable multi 3 sends out an H level pulse C ₁ at time t ₂ . The above H level pulses B ₁ and C ₁ are each FF
It is sent to D terminals 4 and 5. By the way, since the rotation pulse A ₂ is sent out after the pulse B ₁ is returned to the L level due to the relationship T>t ₁ , the Q outputs of FFs 4 and 5 both maintain the L level (signals d, (see e). Since the Q output of the FF 4 is at L level, the selection gate 6 directs only the rotation pulse to the CK terminals of the reversible counters 7 to 10 so as to directly pass the rotation pulse. At this time, the VCO 16 output tracks the rotation pulse itself, but since the tracking ability is at the limit due to the slow sending cycle of the rotation pulse, the rotation pulse itself is used by the selection gate 6 from the viewpoint of operational stability. It is said that In this way, since the reversible counter counts rotational pulses, the direction of the count value is changed by 0.1° per rotational pulse, such as 150.0, 150.1, 150.2, etc., as shown by the signal f. In this case, even though the rotation pulses are counted by the reversible counter 7, the reason why they are also led to the reversible counters 8 to 10 is to ensure counting operations during carry up and down.

Regarding case (b) In this case, as shown in signal a', the rotation pulse is in the range of period t ₂ to _{t 1} , so after the rotation pulse A ₁ ' is sent out, at the time when the rotation pulse A ₂ ' is sent out. In this case, the H level pulse C ₁ of the monostable multi 3 has already returned to the L level, and conversely, the monostable multi 2 is still in the sending period of the H level pulse B ₁ . At this time,
As described above, the monostable multi-pulse 2 operates so as to send out an H level pulse for an additional time t ₁ from the point in time when the rotational pulse A ₂ ' is sent. As a result, FF4 maintains the H level state (signal d'), while FF5 maintains the L level state (signal e'). The H level signal from the FF4 is applied to the terminal "2" of the frequency divider circuit 17, and the frequency division ratio of the frequency divider circuit 17 is set to 1/3. Therefore, a multiplied pulse g' having a period of 1/3 of the rotation pulse is obtained as the output of the VCO 16. At this time, selection gate 6
passes the multiplied pulse g' from the VCO 16 in response to the H level signal from the FF 4, and guides it to each CK terminal of the reversible counters 7 to 10. In this way, since the reversible counter counts the multiplied pulses, the azimuth of the counted value changes by 0.3° per rotational pulse, as shown by f'.

Case (c) In this case, as shown in the signal a'', the rotation pulse is within the period _t2 , so at the time when the rotation pulse _A2 '' is sent out after the rotation pulse _A1' ' is sent out, the monostable multi-2 , 3 are both in the period of sending out the H level pulses B ₁ and C _1. At this time, as mentioned above, the monostable multis 2 and 3 are further away from the point of sending out the rotational pulse A ₂ ″.
It operates to send out H level pulses for hours _t1 and _t2 . As a result, both FFs 4 and 5 maintain the H level state (signals d″, e″), and this H level signal is applied to the terminals “2” and “4” of the frequency dividing circuit 17. Set the frequency division ratio to 1/7. Therefore, VCO16
Multiplyed pulse with 1/7 period of rotation pulse as output
g'' is obtained. At this time, the selection gate 6 passes the multiplied pulse g'' from the VCO 16 by the H level signal from the FF 4, and each of the reversible counters 7 to 10
Lead to CK terminal. In this way, since the reversible counter counts the multiplied pulses, the count value is changed in orientation by 0.7° per rotational pulse, as shown by f''.

As explained above, according to the present invention, if the rotational speed of the rotary encoder is increased, the orientation marker can be rotated even more, thereby facilitating quick setting. Furthermore, since the turning speed of the orientation marker is changed stepwise by 0.1°, 0.3°, and 0.7° per rotation pulse, there is no unnatural feeling when using it.

Although this example is explained in three stages,
Without being limited to this, generally n stages (n
≧2). Further, the frequency division ratio of the frequency dividing circuit 17 is not limited to 3 or 7 frequency division.

Note that in the above, FFs 4 and 5 are a type of logic circuit that exhibits an inverted state according to the cycle of the rotation pulse based on the presence or absence of the rotation pulse within the output sending time of each of the monostable circuits 2 and 3. Therefore, this type of logic circuit is not limited to FFs 4 and 5 in FIG. 1, and can be modified in various ways.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a waveform diagram thereof.

Claims (1)

[Scope of Claims] 1. A radar device comprising: a rotary encoder that sends out a rotational pulse every time the rotational pulse is rotated at a fixed angle; a reversible azimuth counter that counts the rotational pulse; time t ₁ , t ₂ ...t _o (however, n≧2, t _k >t _k+1 ,
1≦k≦n-1), and by detecting the presence or absence of the rotation pulse within the signal transmission time of each of the n signal generation means, the rotation is detected. a discriminating means for discriminating a pulse sending period; a multiplication PLL circuit configured of a PLL circuit, which multiplies the rotational pulse and at the same time controls the multiplication rate based on a discrimination output of the discriminating means; means for using the multiplied pulse as a counting pulse for a reversible azimuth counter in place of the rotational pulse based on the output of a signal generating means for transmitting a signal at the time t _{1 when t is 0 to t 1 ;} An azimuth marker turning device for a radar device, comprising: an azimuth indicator that displays a numerical value indicated by a reversible counter; and azimuth marker display means that displays an azimuth marker in the azimuth direction on a radar signal display.