JPS6011864B2 - signal transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal transmission device that secretly transmits and receives information signals between a main device and a plurality of sub devices.

In particular, the present invention relates to a signal transmission device that transmits and receives the above-mentioned information signals via a wireless transmission path. This type of signal transmission device can be used, for example, by the operator of the main device (for example, a teacher)
The operator (e.g. student) of each main device shall
A device that sends a response (for example, information indicating the answer branch that is considered the best) to the given information (for example, a question and a group of answer branches) back to the above-mentioned main device is used for educational purposes, data aggregation, etc. It is being

In general, this type of signal transmission device sends and receives information signals via wired transmission lines interposed between the main device and each sub-device, so it requires complicated installation. This was extremely inconvenient as it required wiring and had to be installed at a fixed location.

By the way, in order to solve the above-mentioned drawbacks of the conventional example, it is possible to send and receive information signals between the main device and each device using a wireless transmission path. If multiple carrier waves with different frequencies are transmitted, each with a superimposed information signal, and the main device selectively receives the carrier waves with superimposed information signals from each sub-device, interference between the carrier waves will occur. As a result, the quality of the information signal deteriorates, and the configuration of the main device and each Liu device becomes extremely complicated, making it impractical.

Therefore, in the present invention, when transmitting and receiving information signals between the main device and each sub-device via a wireless transmission path, each Liu device converts a carrier wave of the same frequency into a chopping signal of a different frequency with a line return frequency. The main device transmits intermittently according to the above-mentioned chopping signals, and the main device calculates the number of sub-devices transmitting the above-mentioned carrier waves by receiving the carrier waves from each of the above-mentioned stations and integrating them for a predetermined period. The object of the present invention is to provide a novel signal transmission device that eliminates the above-mentioned drawbacks by performing discrimination using the asynchronicity of the signals.

Hereinafter, the present invention will be described in detail with reference to the drawings.

First, the basic principle of the present invention will be explained.

The ratio of time for transmitting information signals to the main device with respect to unit time is Q%, and the second ratio is P%.
When the main Hishitaka receives information signals transmitted from the secondary device of y% and the third secondary device of y% (here, Q, 8
, y are determined by the ratio of "1" and ro" of the chopping signal.) First, if the first and second sub-devices are transmitting each information signal, each information signal is If we consider a very long time to be "1", the probability that the information signals exist at the same time is shown in Figure 1.The probability that the information signals from the first and second Hatake0 bags exist simultaneously is 3).Thus, when an information signal is transmitted from one of the first or second sub-devices or both the first and second sub-devices, the information signal is represented by one of them. The existence probability of (
P,) is P,! It becomes Q+3-Q・8.

Similarly, the probability (P2) that any of the information signals from the first, second, and third subdevices exists within a unit time is P
2=P, 10y−P,.

y= is 10B+y-Q18-8・y-y'Q1Q・B・so.

Furthermore, if the existence probability of the information signal is 6, and which fourth and fifth sub-devices are added, the difference ΔP in the probability that the main device receives the information signal is P21P,iyo(11P, ) P3-P2=6. (11y). (1-P,)P4-P3
= Go●(1-6)-(1-y)・(1-P,).

Here, with M sub-devices, Q=B=y=...=N
In this case, the above difference △P is △P=N・(1-N)...1
...This is the first equation.

Therefore, in the first equation, since N times 1, the difference (△P) approaches "0" as the number of sub-devices (M) increases, so the number of sub-devices transmitting information signals can be discriminated. The value of M is determined as shown in FIG. 2 depending on the accuracy (disassembly) and the time used for discrimination. Therefore, a chopping signal (f,,mo,mo......f
n) is assigned to each sub-device, and an information signal is transmitted from each Liu device in response to the above chopping signal.
The main device can discriminate the number of sub-devices transmitting information signals by performing number discrimination with a finite integration time within a range that allows for errors in number discrimination.

Next, FIG. 4 shows an embodiment of the present invention. In the figure, reference numeral 10 denotes an information signal input circuit consisting of a switch 11 and a latch circuit 12. Reference numeral 13 denotes an oscillator that outputs a carrier wave signal frequency-modulated with a modulation signal having a frequency of fM from the local oscillator 14.

Reference numeral 15 denotes an AND date circuit which outputs a logical output signal of the information signal from the information input circuit 10 and the chopping signal from the chopping signal generator 16.

17 converts the carrier signal from the oscillator 13 into the A
This is an electronic switch circuit that selectively supplies the high frequency amplifier circuit 17 according to the AND output signal from the ND date circuit 15.

Reference numeral 19 denotes a transmitting antenna for transmitting the carrier wave amplified via the high frequency amplification circuit 18 described above.

20 is a first sub-device comprising the above-mentioned components. 'Therefore, the first wealth.

When transmitting an information signal from the storage device 20 to three main devices (to be described later), the latch circuit 12 is latched by opening the switch 11 of the information signal input circuit 10.
1'' is applied to the first signal input terminal of the AND gate circuit 15, and the chopping signal from the chopping signal generator 16 is applied to the electronic switch circuit 17 via the AND gate circuit 15 in front of the top. The frequency-modulated carrier wave from the oscillator 13 is transmitted via the antenna 19 only during the period when the chopping signal is ^1''. Although not shown, the second, third, .

However, the chopping signal from the chopping signal generator has a different repetition frequency for each burial layer, and
The duty ratio is made equal. Also, 30 is
The main structure is as described below.

That is, the carrier wave from the above sub-device is received by the receiving circuit 22 via the receiving antenna 21. Furthermore, the received carrier wave signal is applied to an integrating circuit 24 via a bandpass filter 23 whose middle frequency is fM, and the above-mentioned integrating circuit 24 converts the temporally varying carrier wave signal into a DC signal. Then, the signal level of the DC signal is detected by the bell detection circuit 25, and the number of sub-devices transmitting the information signal is determined from the detection result.
The number is displayed on the display circuit 26, and V is supplied to the data aggregation circuit which is not transmitted as a data signal. That is, in the signal transmission device according to the present invention, for example, the first sub-device 20 transmits a carrier signal as shown in FIG. If a carrier wave signal as shown in FIG. 0' is transmitted to the main device 30 as an information signal, the main device 3
The output signal of the filter 23 that passes through the Obijo filter 23 has a waveform as shown in FIG. By integrating the signal in the integrating circuit 24, a signal having a signal level corresponding to the number of Toyama devices transmitting the carrier wave signal can be obtained.

Although the duty ratio of the chopping signal of each sub-device is set equal here, the information signal from each sub-device can be weighted by changing the duty ratio depending on the sub-device.

Furthermore, FIG. 6 is a block diagram illustrating another embodiment of the present invention in the case of transmitting multiple-choice information signals from the sub-device to the main device. In the embodiment shown in the figure, the same components as in the embodiment shown in FIG. First, the first
The information input circuit 10 of the sub-device 20 consists of first, second...n switches (11a, 11b...11n,) and a latch circuit 12.
. . . 11n) is closed, the latch circuit 12 operates to latch, and outputs a signal "1" to the AN
The signal is released to the first signal input terminal of the D gate circuit 15.

In addition, the latch circuit 12 has its first, second...
・Respectively, the first, second, etc. are connected to the n-th signal output terminal.
n-th local oscillator (14a, 14b,...14n)
are connected to the respective control terminals of the first, second, ... n-th local oscillators (14a, 14b, ... 14n) corresponding to the closed switch. ) is driven. And the above 1st, 2nd, etc.
... n-th local oscillator (14a, 14b, ......,
14n) are different frequencies, and a signal of a specific frequency is applied to the oscillator 13 as a modulation signal in response to closing of the above-mentioned switch. here,
The second, third...Nth sub-device is also the first sub-device 20.
It has a similar configuration. However, the frequency of each chopping signal is different for each sub-device.
Further, the main device 30 receives the carrier wave signal from each of the above-mentioned sub devices in the receiving circuit 22 via the receiving antenna 21, and receives the carrier wave signal from the first, second, . Phil evening (
23a, 23b...23n).

Here, each passing center frequency of the first, second, ..., n-th band pass filter (23a, 23b, ..., 23n) is the first, second, second, and third band pass filter of the above-mentioned sub-device.・・・・・・Nth
The oscillation frequencies of the local oscillators (14a, 14b, . . . , 14n) are set equal to each other. The signals that have passed through each of the band pass filters (23a, 23b, . . . 23n) are sent to the first, second, . . . nth level detectors (25a, 25b, . . . ...25n) is applied to the first, second, ..., n-th integrating circuits (24a, 24b, ..., 24n) connected to their output sides. Therefore, in the embodiment configured as described above, for example, when the first switch 11a of the first sub-device 20 is opened, the first local oscillator 14a is driven, and the oscillator 1
A carrier wave signal modulated by the oscillation frequency of the first local oscillator 14a, which is output from the first local oscillator 14a, is intermittently transmitted from the transmitting antenna 19 via the electronic switch 17 in response to the chopping signal.

Therefore, the main device 30 uses the first local oscillator 14a described above.
A first bandpass filter 24a corresponding to the oscillation frequency of
The above carrier wave signal passing through is converted into a DC signal by the first integrating circuit 25a, and the first level detector 25
The signal level of the above DC signal is detected at point a. Similarly, for the second, third, etc. n-th sub-devices, when any of the switches of the information signal input circuit is closed, the local oscillator corresponding to the closed switch is activated. A carrier wave signal that is driven and modulated at the oscillation frequency of the local oscillator is intermittently transmitted to the main device 30' in response to a chopping signal determined for each sub-device. Furthermore, the carrier wave signals from each of the above-mentioned sub-devices are received by the main device 30, and each band passing filter corresponding to the modulation frequency (
24a, 24b, . . . , 24n), and each integrating circuit (25a, 25b, . . . , 25n) converts the signal into a DC signal. Then, the signal level of each of the above DC signals is determined by each level detection circuit (26a, 26b...2).
6n). Therefore, each signal level of each DC signal detected by each of the above level detection circuits (25a, 25b...25n) is Since it corresponds to each number, it becomes a signal indicating how many sub-devices have closed which switch.As mentioned above, according to the embodiment shown in FIG. According to the present invention, information signals can be selectively transmitted to the main device using a carrier wave having a frequency of Information signals can be sent and received using a carrier wave, and the oscillation frequency of the local oscillator for modulating the carrier wave can be the same for each sub-device, making manufacturing extremely easy.
Cost reduction can be achieved.

Therefore, the intended purpose can be fully achieved. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2, and 3 are diagrams for explaining the principle of the present invention.

FIG. 4 is a block diagram showing one embodiment of the present invention. FIG. 5 is a time chart explaining the operation of the above embodiment. FIG. 6 is a block diagram showing another embodiment of the invention. 10... Information signal input circuit, 13.
...Oscillator, 14, 14a, 14b...14n...
-Local oscillator, 15...AND gate circuit, 16...chopping signal generator, 20...first sub-device, 23,
23a, 23b...23n...Obijo passing filter evening, 24,24a, 24b...24n
......Integrator circuit, 25, 25a, 25b...25
n...Level detector, 30...Main device.

Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Figure 6

Claims (1)

[Claims] 1 In a signal transmission device that exchanges information signals between a main device and a plurality of sub devices, a carrier wave signal of the same frequency that is intermittently transmitted from each sub device in response to a chopping signal with a different repetition frequency. is used as an information signal,
A signal transmission device characterized in that the number of sub-devices transmitting the information signal is determined by receiving the carrier wave signal in the main device and integrating it for a predetermined period.