JPS5890845A - Analog signal transmission device for a plurality of channels - Google Patents

Abstract

PURPOSE:To decrease the number of signal lines, by transmitting an analog signal of a plurality of channels corresponding to a plurality of slave devices to one signal transmission line. CONSTITUTION:A scanning clock signal to scan each switch of all slave devices SL is outputted from a timing section 1 of a master device MS and transmitted to SL1-59 via a line LCK. The SL1-59 scan each switch in time division, and detect the on/off state of the switch to form a binary information signal, which is transmitted to the MS via a line LSG. In the MS, this signal is transmitted to an exchange section 2 and a various-set processing section 3. At each 512th block, stand address data and key address data are sequentially outputted from an exchange section 2 and transmitted to a musical tone waveform synthesis section 6, where the musical tone waveform at each key designated from the addresses is synthesized with the digital operation processing. The synthesized musical tone waveform is divided in time in the unit of transfer stand time corresponding to each slave device at a time series demodulating section 7, D/A-converted and transmitted to each SL via a line LAS.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-channel analog signal transmission device, and in particular, the present invention relates to a multi-channel analog signal transmission device, and in particular, for example, analog signal transmission from a master device, which is a common sound source in a group music learning device, to a plurality of slave devices via a single signal transmission line. This is suitable for transmitting audio signals (musical tone signals).

As a device that handles multiple channels of analog signals,
For example, based on performance information signals from multiple slave units equipped with keyboard sections, musical sound waveforms are intensively synthesized on the master unit side, and this synthesized musical sound signal (multiple channels) for each slave unit is generated. There is a master-slave type group music learning device that sends the music to each slave device. In such a group music learning device, if multiple channels of musical tone signals corresponding to each slave unit are to be sent from the master unit to the slave unit, one analog signal transmission line is required for each slave unit. is,
As the number of output terminals and amount of wiring on the master side increases,
This method has the drawbacks of increasing construction costs and reducing the reliability of the system as a whole.

Furthermore, in a language classroom system, the so-called LL system, an analog signal transmission line for each slave unit is required when transmitting audio signals between each slave unit for students and the master unit for teachers. Similar drawbacks arise.

The present invention eliminates such conventional drawbacks, and provides for example 1
Multiple channels of analog signals (music signals, audio signals, etc.) that correspond to each slave device using a main signal transmission line
The purpose of the present invention is to provide a multi-channel analog signal transmission device capable of transmitting.

Another object of the present invention is to provide a multi-channel/channel analog signal transmission apparatus that can reduce mutual interference between analog signals of each channel transmitted in a time-division manner, so-called crosstalk.

That is, the feature of the multi-channel analog signal transmission device according to the present invention is that the multi-channel analog signal transmission device transmits a plurality of channels of analog signals corresponding to a plurality of slave devices from a master device to each of the slave devices, respectively. The master unit is provided with means for time-division multiplexing multiple channels of analog signals corresponding to the plurality of slave units, and each of the slave units is provided with a gate signal generation circuit, an analog switch, and a low-pass filter. The multi-channel time-division analog signals from the machine are sent to each slave machine via a signal transmission line commonly connected to the slave machines, and each slave machine transmits the multi-channel time-division analog signals. A gate signal is generated from the gate signal generation circuit of the slave unit corresponding to the channel selected in time division, the analog switch is turned on, and only the analog signal corresponding to the slave unit is transmitted through this analog switch. The method is to selectively extract the signal and restore it to the original temporally continuous analog signal using the low-pass filter.

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows the entire group music learning device to which a multi-channel analog signal transmission device as an embodiment of the present invention is applied. No. 89492 and patent application No. 56-90844
This figure shows an example in which the present invention is applied to the group music learning device disclosed in No. 1, etc.

In FIG. 1, each of the plurality of slave machines SL is equipped with at least a keyboard section, and performance information signals obtained by keystroke operations on these keyboard sections are sent to one master machine MS. The master machine MS performs musical sound waveform synthesis intensively based on the performance information signals from each slave machine SL, and sends the synthesized musical sound waveform signals separately to the corresponding slave machine sections.

Here, the performance information signal from each slave machine SL is
Although each slave unit may be sent in parallel to the master unit MS via a plurality of independent transmission lines, in this embodiment, the performance signals of multiple units are transmitted on the time axis. By allocating time-sharing signals to areas that do not overlap with each other, performance information signals from multiple slave units can be transmitted serially (serially) to the master unit MS using a signal transmission line for one slave unit. I am sending it to Furthermore, the performance information signal of one slave machine SL may include a key information signal related to the keystroke operation of the keyboard section, and various setting information signals such as instrument type settings and effect settings such as vibrato and tremolo. These multiple types of signals may be transmitted in parallel through multiple transmission lines, but in this embodiment, these are serially transmitted through one signal transmission line. Therefore, performance information signals from all slave machines can be sent to the master machine through one signal transmission line.

First, as a configuration for performing such signal transmission,
The keyboard section provided in each slave machine SL is provided with a group of key switches that turn on and off in response to the keystrokes of each key on this keyboard section, and these key switch groups are time-divisionally operated using scanning signals. The keys are scanned sequentially, and at each scan timing, a binary signal indicating the state of the corresponding key is output. In addition, each slave unit SL has a group of various setting switches such as setting the type of musical instrument sound, setting automatic performance, and setting effects such as vibrato, and these switch groups are also scanned in a time-division manner by the scanning signal. Ru. In this case, the key switch group and the setting switch group are sequentially scanned in a time-division manner using a single scanning signal.

Here, the master machine MS is one that can connect up to 64 slave machines SL, and the total number of switches of one slave machine SL is, for example, 64 (49 key switches and various settings/settings). (15 switches), the number of time slots to scan all the switches of all slave machines is 64×64=4096. In other words, one scanning period is 4096 time slots, and 6
All 64 switches of each of the four slave machines are repeatedly scanned.

By the way, for these 4096 time slots,
Introducing a 6-bit machine address SA1 and a 6-bit key address KA, the machine address 8A controls one of the above 64 slave machines, and the key address KA controls all 64 switches of one slave machine. one of them,
Each is specified.

In the embodiment shown in FIG. 1, for example, 56 student slave machines SLI, 8L2. ..., a total of 59 slave machines consisting of 5L56 and three teacher slave machines 5L57.8L58 and 5L59 are connected, and the allocated time for the remaining 5 machines within the above l scanning period is as follows. For example, it can be used to place a synchronization signal or when a slave machine from 60 units 0 is added as a backup.

Next, to roughly explain an example of the internal circuit configuration, first, from the timing section 1 of the master machine MS, there is a
o96 time slot scanning clock signal is output,
This scanning clock signal is transmitted to each slave machine 8Ll-8L via, for example, one clock signal transmission line LcK.
59 respectively. For individual or slave devices, 64 time slots that do not overlap with each other are taken out of the 4096 time slots, and each of the 64 switches is sequentially time-divisionally scanned using these 64 time slots, and this scanning timing is The on/off state of each switch is detected, for example, °l", "0", or °H", °L.

A binary information signal expressed as , etc. is output. The binary information signal that detects the state of each switch is output in 64 time slots for each slave machine, and the time slots from all 64 slave machines, including invalid machines, are made so that they do not overlap with each other. It becomes a binary display switch state detection signal for all 4096 time slots.
For example, it is sent to the master machine MS via one signal transmission line Lsa.

In the master machine MS, the switch state detection signal from each slave machine SL is sent to the exchange section 2 and the various setting processing section 3. The various setting processing section 3 is for outputting various setting data and information according to the on/off states of various setting switches other than the key switch. Among the outputs from the various setting processing section 3, setting data regarding automatic performance, etc. is sent to the automatic performance section 4. This automatic performance section 4
The automatic performance signal and automatic rhythm generation signal are sent to the exchange section 2.
, or sent to the musical sound waveform synthesis section 6. By the way, the exchange unit 2 uses the machine address SA of the time slot in the keyed state (key switch ON state) among the time slots corresponding to the key switch of the switch state detection signal.
and key address KA, and allocates these detected machine address SA and key address KA as data to, for example, 512 blocks, and sequentially and repeatedly outputs each data of these 51.2 blocks in a time-division manner. be. In this case, the time division scanning timing of the 512 blocks can be set independently of the scanning clock.
The timing can be set in accordance with the waveform synthesis calculation processing in the musical sound waveform synthesis section 6. Here, the reason why the number of blocks is 512 is that the maximum number of connectable slave devices is 6.
This is to enable each of the four units to produce up to eight notes simultaneously, and generally when playing one keyboard instrument (
This is done in consideration of the fact that it is sufficient to be able to produce sounds by superimposing up to eight tones. However, since a total of 64 units can produce 512 tones in a superimposed manner, it is also possible for a single slave unit to simultaneously produce 9 or more units.

In this way, the address data SA is sequentially transmitted from the exchange unit 2 to each of the 512 blocks.

KA is output and sent to the musical sound waveform synthesis section 6, and in this musical sound waveform synthesis section 6, these addresses SA, KA
The musical sound waveform of the key section specified by is synthesized by, for example, digital arithmetic processing. This synthesized musical sound waveform is also sequentially outputted in a time-division manner for each of the 512 blocks mentioned above, and in the time sequence demodulation section 7, for example, the keys that are in the sounding state at the same time are outputted to each slave unit. The musical tones are added and output as musical tones for each slave unit. The output signal from the time series demodulator 7 at this time is considered to be the result of time-division multiplexing of 64 channels of digital musical tone signals corresponding to all the slave units, and the unit time of this time division (this is referred to as the transfer unit time) ) is a time-division signal in which 64 channels are collected to form the transfer cycle of all channel channels. During the one transfer unit time, a musical tone signal of the corresponding slave machine, that is, a musical tone signal obtained by adding and synthesizing the musical sound waveforms of all the keys in the one slave machine that have been pressed and are in a sounding state is output. The digital musical tone signal which is time-divided by the time unit of the transfer table corresponding to each slave device from the time series demodulator 7 is sent to a digital-to-analog converter (D-A converter) 8, It is output as a time-division analog signal converted into an analog signal (peak value signal) every time.

FIG. 2 shows transfer table addresses tsA of 0 to 63 sequentially attached to each transfer table time within the one transfer cycle of the time-division analog signal. This time-division analog signal consists of all 64 signals mentioned above.
64 channels of analog signals corresponding to the slave machines are time-division multiplexed, and for each slave machine, one analog signal, that is, a sampling peak value signal, is obtained for each transfer cycle.

Therefore, the sampling clock frequency of the musical tone signal of one channel is the reciprocal (for example, 20 kHz) of the one transfer period (for example, 50μ).

Further, the transfer table time is, for example, 50μ(6)÷64
It is approximately 0.78 μm□□.

Such time-division analog signals are sent to each slave machine SL via a resistor R and one analog signal transmission line LA8 commonly connected to all slave machines. Each slave machine SLl, SL2. ..., gate signal generation circuits GC1, GC2, ..., analog switch SWI
, SW2. ..., and low-pass filter LPFI,
LPF2. ... are provided, and each low-pass filter LPFI.

LPF2. The output from ... is the monitor terminal TMI, TM2 to which monitor speakers, headphones, etc. are connected.
．． It is being sent to... Here, in this embodiment, two switches 5Wla, SWtb, SW2a, 5w2b, and
..., these analog switches SWl a
, 8Wt b, 8W2a, 5W2b, , -0 are connected to the analog signal transmission line LAS, and the resistance value of the other end of the analog switch SWI a , SW2 a , ... changes in conjunction with the expression pedal, etc. Connect the variable resistors VRI, VB2, . . . to the analog switch 5Wlb.

5W2b, . . . the other end is connected to the above low-pass filter LPP
I, LPF2. ...is connected to... These analog switches 8Wla, SWIb, SW2
a.

5W2b, . . . are gate signal generation circuits GCI, GC.
Gate pulse signal GP l a from 2,...
GPib, GP2a, GP2b, . . . are controlled to turn on and off, respectively. Furthermore, one end of the switch SWM is connected to the connection point between the resistor R in the master machine MS and the analog signal transmission line LAS, and the other end is grounded.

This switch SWM is used for channel switching of the above-mentioned multiple channel time-division analog signals (the above-mentioned transfer table address tsA
By turning it on at the timing of switching), the output level is returned to O, thereby preventing mutual interference between adjacent channels on the time axis, that is, so-called crosstalk. An example of the time-division analog signal on the signal transmission line LAs at this time is shown as a signal As in FIG. 2, and the on/off operation of the switch SWM is shown as a waveform 8WMP in FIG. 2, respectively. Also, at this time, each slave machine SLl, S
L2. ...analog switch 8Wla.

・S W l b , S W 2 a , 8 W
'lb, . . . For example, the gate pulse signals GP1a and GP1b in FIG.

The on/off control is performed by Qp2a, GP2b, . . . , respectively. These gate pulse signals are applied to the switches 5Wla, 8 on the side of the variable resistors VR1, VR2,...
When W 2 ap... is turned on, the analog word As
Since the level of changes with a time constant curve, the point at which this level stabilizes, for example, for each next channel (
Just before switching to the next transfer table address), press the switch SW.
Ib, SW2b,... are turned on, and this stable level analog signal is passed through the low-pass filter LPFl.
, LPF2,... In addition, switch S
WI b , sw2 b , ,.

and low-pass filter LP)'l, L1'Fz, 19. Insert and connect a level hold circuit between each stop, until the same transfer platform address is reached in the next transfer cycle (approximately 50μ
m□□) The analog level may be held.

Furthermore, the gate signal generation circuits GCi, GC2, . . .
For example, based on the clock signal obtained from the timing section 1 via the clock signal transmission line LCK, each of the gate pulse signals GP1a, GP1b, GP2a, GP2
b..4 Note that as shown in Fig. 3, the count output from the 6-bit counter 11 that inputs the clock signal of the channel switching period (the above-mentioned transfer table time period), the table setting switch, It is also possible to use a device in which the comparator 13 compares the 6-bit machine setting data from the section 12 and obtains the gate pulse signal from the comparison output.

In this case, the count output from the counter 11 becomes the transfer table address tsA, and a synchronization signal of the transfer cycle is supplied to the reset terminal of the counter 11 in order to synchronize the master machine and each slave machine. This is desirable.

As is clear from the above description, according to the multi-channel analog signal transmission device according to the present invention, it is possible to send multi-channel analog signals corresponding to a plurality of slave devices via a single signal transmission line. Therefore, the number of lines is small and signal line installation work can be done easily and inexpensively.
Reliability is also improved.

Furthermore, according to this embodiment, since the signal level is returned to O when switching channels of time-division analog signals of multiple channels, crosstalk between signals of channels arranged temporally adjacent to each other is effective. can be prevented.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and can be easily applied to, for example, a language teaching system in addition to a group music learning device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example in which a multi-channel analog signal transmission device as an embodiment of the present invention is applied to a group music learning device, FIG. 2 is a time chart for explaining the operation, and FIG. FIG. 2 is a block circuit diagram showing a specific example of a signal generation circuit. MS・・・・・・・・・Master machine SL・・・・
・・・・・・・・・ Slave machine 6・・・・・・・・・・・・
...Music sound waveform synthesis section 7...
...Time sequence demodulation section 8......
D-A converter GCI, GC2, ... ...
Gate signal generation circuits 5Wla, 5Wlb, 8W2a, 8
W2b, −・−・・・・A analog switch

Claims (1)

[Claims] In a multi-channel analog signal transmission device that transmits a plurality of channels of analog signals corresponding to a plurality of slave machines from a master machine to each of the slave machines,
A means for time-division multiplexing multiple channels of analog signals corresponding to the plurality of slave devices is provided on the master device side, and a gate signal generation circuit, an analog switch, and a low-pass filter are provided on each slave device side. The multi-channel time-division analog signal from the master machine is sent to each slave machine via a signal transmission line commonly connected to the plurality of slave machines, and each slave machine transmits the multi-channel time-division analog signal. A gate signal is generated from the gate signal generation circuit of the slave device corresponding to the time-divisionally selected channel, the analog switch is turned on, and only the analog signal corresponding to the slave device is transmitted through this analog switch. A multi-channel analog signal transmission device characterized in that the signal is selectively extracted and restored to the original temporally continuous analog signal using the low-pass filter.