SU600598A1 - Electronic device for tuning musical instruments - Google Patents

Description

one

The invention relates to the field of electromusical instruments.

A device for adjusting EMR is known, comprising an acoustic sensor, an audio amplifier, a precision frequency to voltage converter, frequency dividers, comparators 1.

This device does not provide fine tuning of electromusic instrument.

The closest in technical essence to the invention is an electronic device containing an acoustic sensor, which through a series-connected amplifier, filter unit and the first driver is connected to the first inputs of two time selectors, a crystal oscillator, the output of which through the second driver is connected to the second input of the first time selector whose third input is connected to the output of the reference period setting block, whose input is connected to the output of the first time selector, and its second The output is connected to the fourth input of the first time selector and connected to the corresponding output of the control unit, a gate driver, the output of which is connected to the input of the control unit and the second input of the second selector time 11O1o, and the inputs are connected to the output of the reference period setting unit and the control unit, n

a counter, the inputs of which are connected to the outputs of the second time selector and the control unit 2. The disadvantage of the device is that the tuning accuracy is insufficient.

The purpose of the invention is to improve the precision and simplify it.

The unallocated goal is achieved by the fact that in a device containing an acoustic sensor,

which, through a series-connected amplifier, filter unit and first driver, is connected to the first inputs of two time selectors, a crystal oscillator, the output of which through the second driver is connected to the second input of the first time selector, the third input of which is connected to the output of the installation unit for this period, whose input is connected to the output of the first time selector, and its second output

connected to the fourth input of the nerve temporal selector and connected to the corresponding output of the control unit, the gate driver, the output of which is connected to the input of the control unit to the second

the input of the second time selector, and the inputs are connected to the output of the reference period setting unit by the control unit, an electronic counter, the inputs of which are connected to the outputs of the temporary time selector and

the control unit, the unit for setting the measured period is entered, the first input of which is connected to the output of the first shaper, the second input is connected to the corresponding output of the control unit, and the output is connected to the corresponding input of the strobe pulse shaper.

The structural electrical circuit of the device is shown in the drawing.

The device contains an acoustic sensor 1, an amplifier 2, a filter block 3, a shaper 4, a measured period setting block 5, a strobe pulse shaper 6, a time selector 7, a crystal oscillator 8, a shaper 9, a reference period setting block 10, a time selector 11, an electronic counter 12, a control unit 13, frequency multipliers 14-16, and a switch 17.

The principle of operation of the device is as follows.

The audio signal is converted by sensor 1 into electrical oscillations, which are fed to amplifier 2 and then to filter bank 3, where the pitch or overtone of the signal is extracted. From the output of block 3, the signal is fed to the input of imager 4, which converts the signal into a sequence of short unipolar pulses with a period of Tx equal to the period of oscillation on its diode.

The sequence of these pulses goes to block 5. In block 5, the operator sets the number 1731. At the output of block 5, an output pulse will be received after a 1731 pulse of the measured frequency arrives at its input with a period Tx, i.e., after a time interval of 1731 Tx ms. If to block 5 to bring a sequence of pulses with a period of 0.1 or 0.01 TX, then the pulse at the output of block 5 goes through a time interval of 173.1 Tx or 17.31 TX ms. For this, the signal from the output of block 3 is supplied to the input of block 5 through a group of series-connected multipliers 14-16 frequencies with multiplication factors 10 (in the considered example of such multipliers (there are two transmitters).

From the output of block 5, the pulse corresponding to the end of the interval 1731 Tx (or 173.1 Tx 17.317j :) goes to the shaper 6. The first pulse of the measured signal from the input of block 5 goes to one input of the selector 7 and opens it. The subsequent input pulses do not change the states of the selector 7. To the second input of the selector 7, a signal is sent from the generator 8, converted by the shaper 9 into pulses of constant amplitude with steep edges. A highly stable crystal oscillator is the source of a reference frequency of 577123.05 Hz (the period is 1.731 ms). Since the time selector 7 is open, the quartz oscillator pulses pass through it to the reference period setting unit 10.

The operator in block 10 sets the number 1000 Tn (or 100 TC 10 G). where Hn is the period value in microseconds, for which

The signal source of the musical instrument must be configured. At the output of the reference period setting unit 10, an output pulse will be obtained after a 1000 Ta (or 100 Tn, 10 Tn) pulse of a crystal oscillator is received at its input. Since the period of the quartz oscillator is equal to 1.731 ms, the output pulse at the output of block 10 appears in 1731 Tn ms (or through 173.1 Tn. 17.31 Tn). The falling edge of this pulse in block 10 creates a short pulse, which, like the pulse from output of block 5, is supplied to the pulse generator 6. The pulse from the output of block 10 also goes to the selector 7 and closes it. The signals from the outputs of blocks 5 and 10 in the former 6 force the rectangular strobe pulse of duration K 1731A7, where (t takes the values -2; -1; 0; 1; 2, etc., in the considered examples t has the value O, -1 , -2). A pulse is supplied to one input of the selector 11, to the second input of which a signal of the measured frequency is fed as a sequence of short unipolar pulses with a period Tx from the output of the former 4. Pulses with a period Gx pass through the selector 11 and are considered an electronic counter 12.

In this way, inaccuracies are measured directly in cents. The measurement result is displayed in digital form with an indication of the sign. The plus or minus sign is determined in the imaging unit 6 by the first pulse arriving to it. Thus, for example, if the pulse from the output of the reference period setting unit 10 is received first, the + (plus) sign is displayed, and vice versa, when the first impulse from the output of the block 5 is indicated, the - (minus) sign is displayed.

The back of the strobe pulse starts the control unit 13, allowing you to set a continuously adjustable display time of the measurement result, and after its expiration, reset the electronic counter and prepare the necessary device nodes for the next measurement cycle.

Then all the processes are repeated, i.e., the next measurement cycle is automatically performed. A single measurement mode is also possible. The measurement accuracy is improved by including between the output of the filter bank and the input of the time selector several frequency multipliers with multiplication factors equal to ten.

Claims (2)

1. US patent number 3788184, cl. 84-454, 01.21.74. 2. Authors certificate of the USSR M 379888, cl. Q 01R 36/00, 13.02.70.