Patent GB-1409179-A (GB)
Title: Electronic metronomes
IPC: G10H1/40
Filed: 1973-03-16
Abstract: 1409179 Electronic metronomes DAINI SEIKOSHA K K 16 March 1973 [21 March 1972 21 Oct 1972] 12757/73 Heading G3T [Also in Division G4] An electronic metronome comprises a stable frequency oscillator (e.g. tuning fork or quartz crystal controlled) followed by a variable ratio frequency divider, ratio selecting means for selecting as output from the divider an output frequency equal to a desired tempo frequency, a tempo signal generator for producing from the divider output a tempo frequency signal train, and means for audibly and/  or visually displaying the signal generator output. In addition, up-beat, down-beat, medial beat or composite music time sound or visual signals may be produced. The signal generator may include a resonant circuit triggered by the output of the divider and which produces wave trains which are amplified and drive a loudspeaker. In the metronome Fig. 3, the output of a divider chain or counter comprising flip-flops 2F 1  to 2F 6  is passed via a contact Sa and the wiper-arm of a  switch 3SA to a terminal T. The tempo f selector comprises a switch assembly 3SM comprising groups of switches each group being selectable by a single respective push-button. The output Q 9  of a multivibrator 2M 1  is connectable to reset terminals R 1 - R 5  of flip-flops 2F 1 -2F 5  via a selected switch group when closed. Thus if it is desired to divide the output from oscillator 1 by thirty-three, a push-button is operated which closes switches S 1.1  to S 1.5 , the other switches remaining open. To divide by thirtyfive then switches S 2.1  to S 2.4  only are closed, and so on. Thus, when dividing by thirty-three, the flipflops 2F 1  to 2F 5  are reset by the output of m.v. 2M 1 . In this state the divider counter will be in the state 100000 (binary) i.e. 32 (decimal). The signal state in the counter will be reduced by one at every pulse from the oscillator, thus passing through '0' to '-1' (decimal) wherein the binary state is 111111. In this state the multi-vibrator 2M 1  is triggered and restores the counter to its original state thereby completing one cycle of the counter. By dividing the oscillator frequency (166.79Hz) by any of the ratios indicated in Fig. 3 (33 to 63) tempo signals of a desired frequency (208/min to 108/min) may be obtained at the output Q6 of 2F 6  and at terminal T with switch 3SA closed at Sa. Further division by two may be obtained by a flip-flop 2F 7  the output of which is applied to terminal T when the switch wiper is closed on to contact Sb. Still further division by two is likewise obtained by connecting a flip-flop 2F 6 . The output of the divider may be applied to a decoder connected to turn on successively light emitting elements arranged in a line Figs. 4 and 5 (not shown), thereby producing the appearance of a moving light at the same time as the tempo signals are produced. Alternatively a two dimensional light display may be produced Fig. 6 (not shown) to simulate movement of a conductor's baton. In an embodiment Fig. 7 for producing additionally down-beat signals, an additional variable ratio divider 2A receives the output signal at T from the first divider. The divider 2A is similarly controlled by a selector switch assembly 3A and its output is fed to a down-beat signal generator 4A. The output of 4A is superimposed on that from the tempo sound signal generator. Light-emitting elements may also be used for down-beat visual display. In an embodiment Fig. 12 (not shown) medial beat signals and down-beat signals are obtained from the same divider chain (42). A predetermined frequency sound may be produced by the metronome for tuning purposes, as described with reference to Fig. 11 (not shown).