FR2523786A1 - Music transmission system using telephone lines - including keyboard controlled transmitter sending binary signals to electrical sound generator via telephone line - Google Patents

Abstract

The music transmission system includes use of a keyboard instrument with a selection of control buttons or switches. This keyboard instrument produces electrical control signals indicating parameters of the musical notes to be produced, and forms a console at the transmitting terminal. A musical sound generator is situated at the receiver in order to produce music in response to control signals. An encoder transforms the electric control signals into a series of binary pulses for transmission over the telephone line, and correspondingly a decoder transforms these back into music control signals at the receiver. The transmitter may be situated in the exchange so that it may provide signals to several receivers in parallel.

Description

TELEPHONE MUSIC TRANSMISSION SYSTEM
The present invention relates to a system for transmitting music over the switched telephone network.

The transmission channel on an ordinary telephone line or on a channel of a frequency division or time division multiplex line is defined by the Committee
International Telegraph and Telephone Consultative as having a bandwidth between 300 and 3400 Hz. It is therefore not possible to transmit high-fidelity music occupying a bandwidth of 20 Hz to 20 kHz on the lines of the switched telephone network .

 The present invention relates to a system for transmitting music by telephone line in which a keyboard musical instrument or synthesizer is located at the receiving station while the performer is located at the sending station where he has the keyboard and the controls of the keyboard. instrument or synthesizer. If for example the musical instrument is an organ. classic, the keyboards, the pedals and the pull tabs are at the calling station while the hoses and the air valves controlled by electromagnets are at the receiving station. If the musical instrument is an electronic organ, the keyboard and the control buttons are at the calling station while the speaker or speakers are at the receiving station.

 Generally, the musical sound generators are at the receiving station while the control means of these generators are at the sending station.

 Of course if the performer wants to hear himself play, a second local musical instrument is placed at the calling station and the performer commands it directly while he simultaneously remote controls the distant instrument.

 Among the commands for musical tone generators, some such as the keys of the keyboard are actuated at relatively high frequencies, others such as the commands for games or rhythms are actuated at relatively low frequencies.

 We know from French patent application No. PV 78-29930 of October 20, 1978 an electronic organ control process in which the position of certain organ control elements actuated by the organist to play a note or a chord , such as the keys on the manual keyboard or the pedals bars, or to choose one or more games, such as the drawbars or game control buttons, is defined by a bit, O when said element is at rest and 1 when it is at work.

 Binary words corresponding to the successive states of the control elements during a first performance of a musical work are read and memorized, then during a subsequent performance they are extracted from the memory and are used to position the control elements . Each control element, a pull tab or a key on the keyboard for example, is therefore provided with a position detection circuit and with a positioning control circuit.

 In accordance with the invention, the system for transmitting music by telephone line comprises, at the transmitting station, means for controlling musical tone generators at relatively high control frequency and means for controlling musical tones at relatively low control frequency, means for sampling the state of said control means and deducing therefrom bits whose binary value depends on the state of activity or inactivity of these control means, means for grouping said bits into words and said words in frames and multiframes, each word appearing in the memory multiple times depending on the sampling frequency of the states it contains and all the words appearing at least once in the multiframe.

 By way of example, it is assumed that the musical instrument is an electronic organ with 49 keys and 20 control buttons defining games (in the sense of organ music), rhythms, volumes or particular modes of musical expression (arpeggio, etc.). We will say below that the buttons control musical functions. The frame then consists of a NO O byte used for synchronization and the 49 keys are represented by the six byte bits NO 1 to NO 6 and by the first bit of a NO 7 byte. These 49 bits have the same meanings in all frames. The remaining bits have a variable meaning in each frame and take the same meanings with each multiframe. For this purpose, byte N0 7 contains two address bits and depending on the value of this address 00, 01, 10 or 11 the 5 remaining bits of byte NO 7 and the 8 bits of byte NQ 8 have variable meanings, the list of which includes the functions of the 20 control buttons. There are therefore four frames in the multiframe.

Obviously the example given is supernumerary since it comprises (5 + 8) x 4 = 52 bits available by multiframe. The additional bits can be used as will be seen to transmit sound volumes, or generally levels.

Generally, the multiframe comprises N bits the first N1 bits define the commands having the highest frequency (frame frequency) then come log2pl address bits defining p1 addresses followed by
N2 information bits whose meaning changes with each frame, this meaning becoming the same every p1 frame. The N2 bits have a recurrence frequency equal to the frame frequency divided by p1. Then come log2p2 address bits defining p2 addresses followed by N3 information bits whose meaning changes every p1 frame, this meaning becoming the same every
P1P2 frames. The N3 bits have a recurrence frequency equal to the frame frequency divided by Plu2. And so on.

 The invention will now be described in detail with reference to the accompanying drawings in which - FIG. 1 shows the frame of the transmitted signals - FIG. 2 represents the keys of the keyboard with manual control, the buttons of musical functions with manual control and the potentiometers of adjustment of sound level with manual control, all these devices being located at the sending station - Fig. 3 shows the automatic arrangement replacing the manually operated key keyboard, the automatic arrangement replacing the manually operated musical function buttons, all these devices being located at the destination station - FIG. 4 shows the equipment for transmitting music over the telephone line; - Fig. 5 shows the music receiver equipment on the telephone line; and - Fig. 6 schematically represents a music bank in which pieces of music are stored in the form of the frame of FIG. 2.

We will first refer to Figs 2 and 3 which schematically represent the electronic organ chosen as an example of a musical instrument with a keyboard whose music we want to transmit by telephone. This organ includes 49 keys lol to 130 and 131 to 149 which manually control switches forming the crossing points of a matrix with seven rows N1 to N7 and eight columns B111 B121 B211 B22 B31 '32' B41, B42. Line N1 is incomplete and has only one crossing point P1.11 Lines N2 to N7 each have eight crossing points
P2.1l to P2.42
P7.11 to p7.42 7.11 to P7 42
There are therefore 49 crossing points controlled respectively by the 49 manual keys. The keyboard is activated by pulses appearing in sequence on lines N1 to N and collected on one or more of the
1 7 columns B11 to B42 according to the current state of the keys on the keyboard.

 As a result, the state of the keyboard cannot be tested in parallel. that is to say at a given time and that the test of this state requires, as will be seen hereinafter, a buffer memory.

 In Fig. 2, the crossing points are switches positioned manually by means of the keys and the matrix is excited by successive lines, which provides six successive column words plus an additional bit alone.

 In Fig. 3 the six eight-bit words plus the bit corresponding to the 49th key are successively received by the terminals G111 G12, G211 G22 'G318 G32t G41 G42 and the bits are used to position the crossing points themselves, which can be of any what known type, field effect relays or transistors for example.

 They can also be made up of AND gates which scan the cotncidences between lines G and lines N.

In another possible version, the crossing points may not be used, and the outputs
G of a buffer memory 31 (+ the bit of memory 41 corresponding to the 49th note) directly attack the outputs B11 to B42 of the matrix. The memory 31 is supplied with the 6 8-bit words at the rate of reception of the said bits and read at the addresses originating from the coding of the pulses of the lines N of the matrix of the receiver in the address coder 32.

In Fig. 3, the crossing points have been represented in the form of field effect transistors such as T1.11 ′ T2.11 to T7.42
The musical function switches (Figs. 2 and 3) are twenty in number and are designated by the same reference numbers which designate the bits representative of the state of said switches. The list of 20 functions is as follows
D 591) are used to code the choice of a pair of D 601 games among 5 according to the following code: (coder 39)
D 611)
D 591 D 601 D 611
OOO No selection
1 0 O Organ 1 - Organ 2 (901)
O 1 O Trumpet - strings (902)
1 1 O Clarinet - oboe (903)
.O 0 1 Piano - Harpsichord (904)
1 0 1 Accordion - Vibraphone (905)
D 621 Orchestra switch
Choice of 1 among 2 in game pairs.

D 631 Support.

Rhythm switches
D592 market - disco
D602 waltz - rock
D612 tango - swing
D622 rumba - samba D632 rhythm selection
Other functions
D593 measurement variation
D603 synchrome start
D613 start
D613 D623 not used (escape bit) n633 not used (escape bit) D594 plucked rope D604 held rope D614 memory D624 multi-bass D634 arpeggio
In Figs. 2 and 3 these different switches have been shown as having a second blade which, according to
the switch position receives either of two different voltages, a ground and a voltage of -9 volts
for example.

In Fig. 2, the musical function switches
are operated manually. Their condition appears in a
twenty bit register 150. In FIG. 3, these switches are controlled by the signals received at the station
receiver and appear on register 160 also at
twenty bit positions.

The organ also includes a number of potentio
meters shown at 151, 152, 153, 154 which in FIG. 2
are controlled manually,
Referring now to FIG. 1, the com frame takes nine eight-bit words. The first word in each frame is a synchronization word. The frames are grouped into thirty six word multiframes. In each multiframe, the bits of words N 1 to N 6 have the same meaning. On the other hand, the words N 7 and N) 8 have a different meaning depending on the number of the frame in the multiframe. For this purpose, the word N 7 contains two address bits which can take the values 00, 01, 10, 11. Depending on the address value of the frame in the multiframe, the bits of the words N 7 to 74 and 81 to 84 have a special meaning.

The word N 0 containing the bits Do to D7 is a synchronization word,
Words N 1 to 6 have a total of 6 x 8 = 48 bits D8 to D55 which correspond respectively to 48 keys on the keyboard.

The words N 71 to 74 contain a bit D56 which corresponds to the forty-ninth key on the keyboard, 2 bits of address D57 and D58 which we have just spoken and 5 bits of information which according to the address of the frame in the multiframe can take the meanings D591 to 631 'D592 to D632, D593 to D633, to to D
We have previously seen the meaning of these bits.

 Fig. 4 shows the music transmission equipment. The dynamic matrix 10 of the electronic organ has as already seen seven lines N1 to N7 and eight columns Bill, B12, B21, B22 'B31 B32, B41, B42 ... As we said the lines of this matrix are attacked by clock pulses by consecutive lines. The matrix 10 is connected to a buffer memory 11 of six 8-bit words. The number of the row of the matrix is coded in writing in 3 bits by the coder 12. The columns of the memory 11 correspond to the columns of the matrix 10.

 A time base 13 connected to both the organ clock and the modem clock 14 sends read orders and address information to the "write-read" switch 15. The words keys NO 1 to N0 6 are therefore read consecutively after each activity cycle of the matrix 10.

These key words are entered in the Receiver
Universal Synchronous Transmitter (USRT) 16 through an eight-wire bus 17. The USRT 16 is connected to the synchronization word register 18. The synchronization word NO O and the key words N 1 to N 6 are thus transmitted in serial by modem 14 on telephone line 19.

 A second buffer memory 21 is connected to bus 17 and to a register 20. The buffer memory 21 receives a "frame" rhythm from the organ, the key bit P1111 and the groups of five bits D591 - D631 - D592 - D632 '- D593 - D633' - D594 -D634 'mations arriving from register 150 via the parallel serial register 20 which transmits 20 bits not groups of five successive bits. The buffer memory 21 also receives at frame rate from the modem the successive addresses 00, 01, 10 and 11. The successive words n 7 which differ in their informative content are read from the buffer memory 21, introduced in the USRT 16 and transmitted online by modem 14.

Analog digital converters 22, 23, 24, 25 transform the "arpeggio volume", "low volume", "rhythm volume" and "tempo" signals delivered by the potentiometers 151 to 15 into bytes. These bytes D641 - D711, D642 - D712, D643
D713 and D644 - D714 (cf. Fig. 1) are transmitted to the USRT 16 by the bus 17 at the appropriate times fixed by the time base 13.

 These bytes also locally attack digital - analog converters 42 to 45 which act as variable gain amplifiers and which give the signals "Arpeggio", "bass" and "rhythm", volumes proportional to the positions of the potentiometers 151 to 153 and at the tempo control signal a value proportional to the position of the potentiometer 154.

 Referring now to FIG. 5, the words transmitted by the sending station are received by the modem 34 through the telephone line 19, then applied to the USRT 36 whose synchronization input is linked to the modem clock.

 The output of USRT 36 is connected to an eight-wire bus 37.

This bus is connected to a buffer memory 31, a buffer memory 41, a synchronization word recognition circuit 38 and four digital-analog converters 62-65.

 A time base 33 receives timing information from the organ clock, the modem clock 34, the synchronization word recognition circuit 38 and the address bits supplied by the buffer memory 41. time base controls the "read-write" register 35, the buffer memory 41 and the digital-analog converters 62-65.

 The buffer memory 31 with six 8-bit words and identical to the buffer memory ll, receives the words NO 1 to NO 6 at the rate of the modem clock and applies them to the crossing points, 8 by 8, T2.11 to T to the rhythm of the organ clock.

7.42
To this end, the terminals G1 to G42 are successively connected to the columns of crossing points. Lines NO 1 to NO 7 are activated in sequence to the rhythm of the organ clock.

The cross point T1 11 is controlled directly by a bit of the buffer memory 41.

 In another possible version, the terminals G11 to G42 directly attack the outputs B11 to B42 of the matrix.

 The five bits received at each frame in words 7 to 74 are placed in register 40 at the rate of the frame and transferred to register 160 at the rate of the multiframe.

 Words 81 to 84 are converted into analog signals in digital-analog converters 62 to 65 which act as variable gain amplifiers and which give the signals "arpeggio", "bass", "rhythm" volumes proportional to the value of words 81 to 83 and to the tempo control signal a value proportional to the value of word 84.

In the above, it has been assumed that twenty bits of musical functions are obtained in parallel in register 150,
There are organs in which these bits are available in series. In such a memory, the buffer memory 41 plays the roll of the buffer memory 11, but for four five-bit words instead of six eight-bit words.

 We have seen that the frame included 2 escape bits D 623 and D 633. These bits are used at reception to go from "telephone" operation in which the receiving telephone set is connected to line 19 to "music" operation in which this telephone line is connected to the modem and vice versa.

 The invention further relates to the case where a single control station provided with the equipment of FIGS. 2 and 4 is connected by telephone channels to a plurality of receiving stations each provided with the equipment of Figs. 3 and 5. Finally, a plurality of remote-controlled organs 78, 79, ... can, in accordance with the invention, be connected by decoders - demodulators 76, 77, ... to a music bank 75 in which pieces of music are stored according to the frame of Fig. 2.

Claims (6)

 1 - Music transmission system on a telephone channel connecting a sending telephone set to a receiving telephone set comprising  a musical instrument composed of at least one keyboard of keys and a plurality of buttons or switches, the so-called keys and, switches selectively delivering electrical signals for controlling musical parameters, the keyboard and the switches forming a console located at the sending station;  said musical instrument also comprising a generator of musical sounds located at the receiving station and controlled by said electrical control signals;  characterized in that  the console further comprises an encoder transforming said electrical control signals into binary coded serial signals delivered to the telephone channel and the sound generator further comprises a decoder transforming the binary coded serial signals delivered by said channel into electrical signals from control of musical parameters.  2 - Music transmission system on the telephone channel according to claim 1, characterized in that the console is located in a central station and that a plurality of musical sound generators are located in as many receiving stations connected to the central station by telephone channels, the console sending electrical control signals to all musical signal generators in parallel.  3 - music transmission system according to claim 1, wherein the electrical control signals have different frequencies and are sampled at different repetition frequencies to give said serial binary coded signals, characterized in that said binary signals form words which are distributed in frames - themselves divided into multiframes and that the words relating to the relatively high frequency electrical control signals appear in all the frames and that the words relating to the relatively low frequency electrical control signals appear only in some of the multiframe frames.  4 - music transssEsion system according to claim 3, characterized in that some of the words relating to the electrical control signals with relatively low frequency matching include address bits, that said words appear in the multiframe with different addresses and that the information bits of said words following the address bits have a meaning which varies when the address varies.  5 - Music transmission system on the telephone channel according to claim 1 characterized in that the electrical signals supplied by the keys and switches of the console are delivered sequentially by the musical instrument at a rate dependent on a clock included in said instrument and are sent online by a modem at a rate set by said modem and that the console comprises a buffer memory receiving said signals at the rate of the instrument and delivering them to the modem at the rate of the latter.  6 - Music transmission system over the telephone according to claim 1, characterized in that it comprises a music bank (tus) in which a plurality of musical pieces for keyboard and switches for musical functions are stored under the form of binary frames and multiframes and a system of accumulators at said bank, of subscribers having a music apparatus & keyboard and switches of musical functions linked to said bank by telephone.