JPH0228830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discrimination device for classifying measured values into predetermined ranks.

For example, an aperture-priority automatic exposure control camera is equipped with a number of indicator lamps in its viewfinder to confirm the shutter speed. This type of automatic control circuit is configured as a digital circuit for stabilization of operation, integration into LSI, digital display, etc. When displaying the shutter speed, the shutter speed display circuit counts the number of pulses according to the exposure conditions at that time, classifies and displays the counted values into a certain range, and then displays the shutter speed from that display position. The data speed range is predicted to the outside.

Conventionally, this type of rank discrimination circuit requires one comparator for each rank (pulse count value range). Therefore, as the number of ranks increases, the number of comparators increases accordingly, resulting in a plurality of rank setting circuits and large size circuits, which are no longer able to meet the demands for miniaturization of cameras.

SUMMARY OF THE INVENTION It is an object of the present invention to simplify the circuit construction of this type of device and eliminate the drawbacks of the prior art.

Hereinafter, the present invention will be specifically explained based on an embodiment shown in the drawings.

The measured value rank discriminating device 1 of the present invention includes a counter 2, a plurality of rank setting circuits 3 ₁ , 3 ₂ , . . . 3 n,
It is composed of a determination circuit 4 and a control circuit 5.

The counter 2 counts the number of pulses of the pulse signal (S ₁ ) as a measurement value, and converts the counting output to BCD.
It outputs a code signal (S ₂ ) such as
Also, a plurality of rank setting circuits 3 ₁ , 3 ₂ , ... 3n
is provided for each predetermined rank (count value range), and generates a code signal (S ₃ ) such as BCD corresponding to the rank value, and is constructed of, for example, a matrix circuit. Also, the judgment circuit 4
compares the code signal (S ₃ ) of _the rank setting circuits 3 _{1 ,} 3 ₂ , . For example, the comparator 6 is the main part. Furthermore, the control circuit 5 sequentially steps forward with the judgment signal (S ₄ ) as input, and the corresponding rank setting circuits 3 ₁ , 3 ₂ , . . .
...3n, respectively, and is configured with the counter ₇ as the main part. This counter 7 operates upon receiving the start signal (S ₆ ), and the plurality of operation signals (S ₅ ) are as follows:
The outputs are outputted to the rank setting circuits _{3 1 , 3 2 ,} . . . 3n through inverters 8 ₁ , 8 ₂ , .
It is set so that it reaches 0. Incidentally, the rank setting circuits 3 ₁ , 3 ₂ , . . . 3n each have an operation signal (S ₅ ).
The display lamps 11 ₁ , 11 ₂ ,...1
1n respectively, and set a predetermined rank such as overexposure (OVER), shutter speed (1000),
(500)..., underexposure (UNDER) will be displayed externally.

Next, the operation will be explained. For example, assume that the code signal (S ₂ ) of the counter 2 is between the rank setting circuits 3 ₃ and 3 ₄ . First, when a start signal (S ₆ ) is given to the counter 7, the counter 7 outputs an operation signal ₍ S ₅ ) to the first inverter 8 ₁ , which converts it to “L” level and starts the operation signal (S 5 ). Send to the first rank setting circuit ₃₁ . Upon receiving this signal, the unique rank setting circuit 3 which is the first setting value
₁ code signal (S ₃ ) is sent to one side of the comparator 6. On the other hand, the counter 2 converts the measurement value measured at the same time as the start signal (S ₆ ) into a code signal (S ₂ ) and sends it to the other side of the comparator 6. The measured value input to the counter 6 is a group of pulses (S ₁ ) corresponding to the amount of light, so it is not input instantaneously, but the value of the counter 2 increases sequentially over time and is input to the comparator 6. Similarly, the code signal (S ₂ ) gradually rises. Then, the code signal (S ₂ ) which increases sequentially is compared with the code signal (S ₃ ) of the rank setting circuit 3 ₁ , and when they match, the comparator 6 outputs one pulse-like judgment signal ( S ₄ ) is output to the counter 7. Counter 7 uses this judgment signal (S ₄ )
_The output of the operation signal (S ₅ ) is switched to the second inverter 8 ₂ , which converts it to the "L" level and sends it to the second rank setting circuit 3 ₂ . . Then, in the same way as in the first case, the code signal (S ₂ ) and the rank setting circuit 3
₂ code signal (S ₃ ) and when they match,
The comparator 6 again outputs one pulse-like determination signal (S ₄ ) to the counter 7. Similarly below,
The counter 7 increments from the third to the fourth. Since the code signal (S ₂ ) and the code signal (S ₃ ) of the fourth rank setting circuit ₃₄ do not match, the comparator 6 does not output the determination signal (S ₄ ), and the counter 7 It does not move forward and stops at the 4th position. During the above operation, the rank setting circuit 3 ₁ ,
According to the switching of 3 ₂ , 3 ₃ , 3 ₄ , the display lamps 11 ₁ , 11 ₂ , 11 ₃ , 11 ₄ , 9 1 , 9 _{2 ,} 9 ₃ , 9
₄ also switches, and when the counter 7 stops at the 4th position, the lighting positions of the indicator lamps 11 ₄ and 9 ₄ also stop, and the shutter speed (1/250) changes depending on the position.
Display. Note that these display lamps 9 ₁ , 9 ₂ , ...
9n is effective, for example, when inspecting the shutter speed at the camera manufacturing stage without looking inside the viewfinder. Further, this output is simultaneously used as an output of a measuring circuit or the like when printing the speed, or as another processing signal.

Note that although the above embodiment has been described as one for displaying the shutter speed of a camera, the present invention is not limited to this application.

In the present invention, since the control circuit sequentially operates the rank setting circuits, only one determination circuit, especially its comparator, is required, and therefore the rank determination device can be simplified and miniaturized. Since the circuit elements can be composed of general digital circuit elements, such as counters and comparators, the product can be provided at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the measured value rank discriminating device of the present invention. DESCRIPTION OF SYMBOLS 1...Measurement value rank discrimination device, 2...Counter, ₃₁ , ₃₂ ...3n...Rank setting circuit, 4...
Judgment circuit, 5... Control circuit, 6... Comparator, 7... Counter.

Claims (1)

[Claims] 1. A counter that counts pulse signals that express the value of a measured value as a number of pulses and outputs the counted value as a code signal, and a code signal that is provided for each predetermined rank and that corresponds to the rank value. a determination circuit that compares the code signal of the counter and the code signal of the rank setting circuit and generates a pulse-like determination signal when they match;
A measured value rank discriminating device comprising: a counter that sequentially increments in response to the pulsed determination signal and switches the output of the operation signal to the corresponding rank setting circuit. 2. The count rank determination device according to claim 1, wherein the determination circuit is comprised of a comparator. 3. The count rank discriminating device according to claim 1 or 2, wherein the control circuit has a number of display lamps corresponding to a predetermined rank that are turned on in response to an operation signal.