JPH0262873B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electronic circuit having the function of playing a melody. More specifically, it relates to a means for obtaining a scale for playing a melody. FIG. 1 is a block diagram showing the general configuration of an electronic clock with an alarm, which is an electronic circuit. first,
The heart of the clock is an oscillation circuit 1 using a crystal oscillator, and its oscillation frequency has a value of approximately 2 ⁿ (n is a natural number). That is, 65536Hz, or
131072Hz etc. are common. Next, this oscillation output enters a frequency divider circuit 2 of more than 10 stages that successively reduces its frequency by 1/2, and is finally taken out as a 1 second signal. The second signal is 60 in counter circuit 3.
It is converted to decimal or decimal and integrated into hour, minute, and second signals. Each time signal is further encoded for digital display in a decoder 4, and is displayed on a display 6 such as a liquid crystal via a driver 5. On the other hand, for the alarm function, there is also an alarm time setting circuit 7, in which the alarm time is inputted by an external switch. The input signal is immediately encoded and the time coincidence detection circuit 8
At this point, a comparison is made with the current time, and when they match, the electroacoustic transducer 9 notifies you with a buzzer sound. The above is the normal configuration of an electronic watch with an alarm. The present invention realizes a melody scale forming circuit that forms a scale frequency with less error relative to the frequency specified in the international convention, in order to cause an electronic circuit such as the above-mentioned electronic clock with an alarm to play a melody. FIG. 2 is a block diagram of a melody scale forming circuit according to the present invention, looking in detail at the electroacoustic conversion portion of FIG. 1. In FIG. 2, the same oscillation circuit 10 as the time standard in FIG. 1 is used as a reference signal source, and its output is connected to a programmable counter 11 which takes out the divided frequency appropriately corresponding to the musical scale. The frequency-divided output of the programmable counter changes successively according to instructions from a memory circuit 15 such as a ROM that stores an arbitrary song. For reading out the memory, etc., the frequency division circuit 14 obtains a frequency divided output based on the standard time signal, and specifies the address of the memory section, that is, the frequency division number that determines the pitch of the song. The read speed of the memory, that is, the tempo of the song or the length of the sound, is controlled by this frequency division output. Therefore, the output of the programmable counter 11 is a series of a plurality of frequencies having different durations, that is, an electrical output corresponding to a melody. Next, this output is transformed into a driving waveform suitable for the speaker 13 through the driver 12, and after being applied with an appropriate amplifier, is extracted from the speaker 13 as sound. Now, in an alarm that plays such a melody, in the present invention, the frequency is 1/1 of the standard frequency.
(64×2 ^m ) (m is an integer) The feature is that the frequency-divided output after frequency division is set as a reference scale, for example, C tone. Table 1 shows the frequency for each note of the scale based on international conventions and ¹ /(64
×2 ^m ) The frequency of the equally divided average rate scale for watches when the divided frequency corresponds to the C note and _C6 note = 1024Hz, _C7 note = 2048Hz, and the programmable counter 11 calculates ²ⁿ The frequency is compared with the frequency when the standard frequency of Hz is divided according to the frequency division number data stored in the memory circuit 15. This table shows that the divided output 2 ¹⁰ = 1024 Hz or 2 ¹¹ = 2048 Hz obtained from the standard frequency 2 ⁿ Hz is very close to the international conventions of C ₆ = 1047 Hz and C ₇ = 2094 Hz. That's true. Therefore, it can be said that it is desirable to set the frequency-divided output of 1024 Hz or 2048 Hz as the approximate C note of the melody scale. Then, based on this approximate C note, form an equally divided average rate scale, and combine that frequency with the standard frequency of 65,536Hz or the standard frequency of 131,072Hz.
If we compare the frequencies obtained by dividing the frequency by an integer using integers between 64×2 ^m and 64×2 ^m−1 , we find that these values also have very close values.

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Claims (1)

[Claims] A reference signal source including an oscillation circuit having an oscillation frequency of 1 2 ⁿ Hz (n is a natural number), a memory circuit that stores frequency division number data corresponding to the scales that make up the melody, and a signal that is read from the memory circuit. 2 ⁿ obtained from the reference signal source upon receiving the frequency division number data.
and a programmable counter that divides a Hz signal to a frequency corresponding to a musical scale, and the memory circuit divides 2 ⁿ Hz obtained from the reference signal source into 64×2 ^m (m
is an integer), and make the frequency divided by the frequency division number correspond to the frequency of the C sound, and convert the 2 ⁿ Hz from 64 × 2 ^m to 64 × 2 ^m-1
Frequency division number data corresponding to the scales constituting the melody is set and stored so that the frequency divided by an integer frequency division number between up to and including approximately corresponds to the frequency of each other scale. A melody scale formation circuit featuring: