JPS583231B2 - Large and small moon discrimination circuit - Google Patents

Description

[Detailed description of the invention] The present invention relates to a size discrimination circuit.

The conventional large/small moon discrimination circuit calculates the monthly count contents from January to 12.
Decode each month, 1, 3, 5, 7, 8, 10, 1
February was considered a large month, and 2, 4, 6, 9, and 11 were considered small months.

However, this circuit requires a decoder to decode each month from January to December, and a gate circuit to select whether the month is a large month or a small month, making the circuit configuration complicated.

The present invention provides a circuit that can discriminate large and small moons with a simple circuit configuration, and one embodiment of the present invention will be described in detail below with reference to the drawings.

As an example, an electronic timepiece having a so-called perpetual calendar function will be described.

FIG. 1 is a plan view of an embodiment (wristwatch) of the present invention.

The month display section 1, date display section 2, hour display section 3, minute display section 4, and second display section 5 indicate that the current time is 6:35:21 on November 18th.

Further, the third column of the day display section 2, which is displayed in five columns of seven days by the Sunday display section 6, ie, the 3rd, 10th, 17th, and 24th, indicates that this month's Sundays are Sundays.

Further, 7, 7, . . . are buttons for modifying the display.

FIG. 2 is a block diagram of the main parts of this embodiment.

A reference signal from a reference pulse oscillator (or commercial power source) 8 is divided by a frequency divider 9, and a second counter 10-5, a minute counter 10-4, an hour counter 10-3, and a day counter 10-2.
, the month counter 10-1 counts seconds to months, and the decoders 11-1, 11-2, . , minutes, and seconds.

The day is displayed in segments 2a and 2 arranged in a matrix.
This is done by selecting one of a, . . .

The month, hour, minute, and second characters on the dial in Figure 1 are fixedly displayed.

Also, the days from the 1st to the 28th in the date display section 2 are fixedly displayed on the dial, but the display sections 2-29.2-302-31 for the 29th, 30th, and 31st are shown in Fig. 3, for example. As shown, a twisted nematic liquid crystal 12, a transparent electrode 13, and a polarizing plate 14 are sequentially laminated on a transparent electrode 11 marked with numbers "29,""30," and "31." It is biased from below.

"29" when no voltage is applied between electrodes 11 and 13;
The numbers ``30'' and ``31'' are visible, but when a certain voltage is applied, the twisted nematic liquid crystal 12 loses its light-dispersion properties, and no light passes through the polarizing plate 14.
”, “30” and “31” cannot be seen from above.

In this embodiment, as shown in FIG.
2 by the unused date display suppression circuit 15 depending on the contents of -1.
9th, 30th, 31st display section 2-29.2-30.2-
For example, in the embodiment shown in FIG. 1, the content of the month counter 10-1 is "11", so the 31st day display section 2-
Only the display of 31 is suppressed.

The output of the unused day display suppressing circuit 15 is fed back to the date counter 10-2 to convey information about how many days the currently displayed month ends.

FIG. 4 is a block diagram for explaining in detail the unused day display suppression circuit 15 of this embodiment.

The month counter 10-1 consists of four binary counters 10-1a,
It is composed of 10-1b, 10-1c, and 10-1d.

Table F shows the binary representation of each month and the distinction between large and small months.

As you can see from this table, the most significant bit (4th bit) is 10-
When the output of 1d and the output of the least significant bit (1st bit) 10-1a are the same, it is a small month, and when they are different, it is a large month. Therefore, use the exclusive OR of the outputs of 10-1d and 10-1a. This output, that is, the 31-day display suppression signal Sig31, obtained by exclusive OR gate Ex-OR and its inversion by inverter Invl, is "1" (logical value 1) only for small months.
is written as “1”, and so on).

Also, by inverter Inv2 and NOR gate NOR, 2
Since it is detected that it is the moon, the output of this Noah gate NOR, that is, the 29th and 30th day display suppression signals Sig29,S
ig30 is “1” only in February.

These suppression signals are fed back to day counter 10-2 to tell it what day this month ends.

Further, the Sunday display register 11-6 is a 7-bit shift register and corresponds to the display on the Sunday display section 6.

The pulse generator 16 receives a 29th and 30th date display suppression signal S.
ig29 and Sig31 are input, and the control signal CS
ig, the logical value “0” of these three suppression signals
Generate as many pulses as there are.

In other words, three suppression signals Sig29, Sig30, Sig
If 31 is “0” “0” “0”, there are three pulses, and “0”
” “0” “1” generates two pulses, “1” “1”
” If it is “1”, no pulse will be generated.

The control signal CSig is generated on the moon's behalf.

For example, when changing from November to December, the three suppression signals are "0", "0", and "1", respectively, so from November to December
When the month changes, two pulses are generated by the pulse generator 16, the Sunday display register 11-6 shifts by 2 bits, and the display on the Sunday display section 6 moves 2 bits to the left.

In the example of FIG. 1, it is now November, and the 3rd and 10th
Sunday... is the Nikkiyaku day, but in December, the Sunday display is 2.
The bit moves to the left, and it is displayed that the 1st, 8th, etc. are Nikkaku days.

Although not shown in this embodiment, it would be more convenient if the 29th day of February of 2007 is displayed, and the 30th and 31st day display portions 2-30.2-31 are made invisible.

INDUSTRIAL APPLICABILITY As described above, the present invention is useful even when applied to an electronic timepiece with a perpetual calendar, and large and small months can be determined with a simple circuit configuration.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a block diagram of the embodiment of FIG. 1, and FIG. 2-30. FIG. 4 is a block diagram of the main part of the embodiment shown in FIG. 1. 10-1: Month counter, 10-1a, 10-1b, 10
-1c, 10-1d: binary counter, 10-2: day counter, 15: unused day display suppression circuit, ExOR: exclusive OR gate.

Claims (1)

[Claims] January is counted sequentially using a 4-bit binary number, and it is determined whether it is a large month or a small month depending on whether the logical values of the most significant bit (4th bit) and the least significant bit (1st bit) are the same. Large and small moon discrimination circuit.