GB1465470A - Music teaching aids - Google Patents

Abstract

1465470 Music teaching aids J B COLESHAW W R C DAWSON and E L JONES 6 May 1974 [7 Feb 1973(2)] 58920/72 and 768/73 Heading G5X A music teaching aid comprises means for producing an electrical reference signal indicative of the pitch of a reference note, means for producing an electrical pupil signal indicative of a note produced by a pupil, means for comparing the two signals and producing an output which denotes if the pitch ratio of the two notes lies within a predetermined range of pitch tolerance or not, and a visual indicator controlled by said output. The means for comparing may include timing and frequency comparison. As described a pupil note derived from an electrical keyboard unit (A, Fig. 1, not shown), is converted to a signal P of the same frequency and input to a corresponding circuit 51a of the comparator 12. The number of P oscillations in a test period T is registered by a counter 49a, T itself being the time for m oscillations of the reference electrical signal Q selected by switch 13 from alternative sources such as another electrical keyboard instrument. Suitable gating arrangements to the latch 50a ensure that the pupil lamp (21a) operates if either the pupil note pitch or timing is outside specified limits. A further lamp 74a may be incorporated in the comparator 12. Pitch errors.-Master counter 40 counts m + 2 oscillations of Q repetitively. After one oscillation a pulse is output along line 47 to reset pupil counter 49a which counts P signal oscillations to a maximum of m + 3. Counter 49a only gives an output when it registers outside the range mŒ2. Counter 40 outputs a pulse on line 48 after m+ 1 oscillations of signal Q and the lamp is thus operated at this time if 49a registers a count outside the allowed range. About 0À1 sec. delay before the lamp operation is introduced through unit 68a by the coincidence detector 44a. Timing errors.-Lack of simultaneity between P and Q signals results in zero output from detector 44a causing the inverter 67a to feed a signal to S of latch 50a, triggering the lamp circuit and also causing a longer delay of about 0À4 sec. in conjunction with unit 68a before the lamp 74a operates. A modification (not shown) suggests incorporating additional latches and lamps in each circuit 51a to indicate if a pupil's note is sharp or flat. In a further embodiment (Fig. 4, not shown) one cycle of the P signal is used to define time T in which oscillations of 90 times the Q frequency are counted. A modification (not shown) uses v cycles of P signal to define T in which time u times the frequency are counted. The pupil signals can be made audible through speaker 63, and if a pupil plays more than one note on a keyboard at a given time either the highest or lowest note can be arranged to function as the pupil note.