JPS596533B2 - Slave station of time division multiplex data gearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data gathering device in which a master station obtains different data from a plurality of slave stations on the same carrier wave, and in particular,
Transmits the carrier wave level of the slave station at the target level only during the time allocated by the master station, and lowers the level at other times to prevent mutual interference of transmitted signals between the slave stations,
This invention relates to a slave station of a time-division multiplex gearing device that enables high-speed and stable data collection.

In general, language teaching devices and questionnaire collection devices are equipped with a large number of slave stations around a master station, and the master station and the slave stations are connected by cables corresponding to the number of slave stations, and information between the two stations is connected. We are doing an exchange.

However, in this case, as the number of slave stations increases, the number of cables described above increases, making the wiring complicated and causing inconveniences such as the need to fix the location of the internal stations. . In contrast, a system has been proposed in which information is exchanged between a master station and a slave station through wireless transmission, thereby eliminating the above-mentioned drawbacks of the conventional system.

In this case, since a plurality of information signals are multiplexed and sent to the master station from a plurality of slave stations, it is necessary for the master station to separate these and determine which slave station the information is from. To this end, it is conceivable to allocate time for transmitting information to each of a plurality of slave stations, and have the master station determine the response of that particular slave station. There are two methods for transmitting a carrier wave from a slave station only within the allotted time: (1) turning the power on and off to turn on and stop the operation of the oscillation circuit; (2) the frequency of the carrier wave (e.g. 50 waves) to each slave station, and (3) changing the carrier wave level. However, although the method (1) described above has a very simple circuit configuration and can be implemented at low cost, it is difficult to stabilize the operation due to the start-up of the oscillation circuit's operation, switching grease, etc. In addition, in the method (2) above, since the same frequency does not exist at the same time, there are advantages such as no interference on the same channel between slave stations, but it is necessary to prepare oscillators with different frequencies for each slave station. Not only must consideration be given to the assembly and arrangement of the slave stations, but also the means for tuning the master station to each slave station, which is used to appropriately select the frequency interval, is also relatively troublesome.
In view of such conventional drawbacks, the present invention provides a gearing device in which a master station obtains different data of the same carrier wave from a plurality of slave stations. At the same time, when receiving, the gain of the amplifier connected to the local oscillator is lowered, and when transmitting, the gain of the amplifier is increased, amplifying the local oscillation frequency signal modulated by the transmitted data, and transmitting it through the above filter. Then, top A
ej. By using method 3), the frequency used by the master station is one wave and the slave station is one wave, thereby simplifying the entire transmission system and creating a new time-division multiplex data gearing device with excellent frequency stability and high-speed operation. The purpose is to provide.

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

The figure shows the block connection diagram of the receiving and transmitting circuit of the slave station.
2 is a transmitting/receiving antenna, and 2 is a filter for transmitting/receiving frequency bands, which is configured so that the pass band can be arbitrarily switched by a control signal during transmitting/receiving.

3 is a high frequency amplifier for reception, and 4 is a local oscillation circuit. During reception, the mixer circuit 5 forms an intermediate frequency signal together with the high frequency input signal, but during transmission, it is used as an oscillation circuit for a transmission carrier wave that is modulated by data. Ru.

6 is an intermediate frequency amplification circuit.

Reference numeral 7 denotes an amplifier that amplifies the carrier wave signal during transmission and supplies it to the filter 2, and is controlled by the control signal so that it amplifies the carrier signal during transmission and is inactive when not transmitting. .

8 is an input terminal for control signals.

Therefore, when transmitting response data from the slave station to the master station, a control signal assigned by the master station is supplied to the input terminal 8, and the control signal causes the carrier frequency (F8 ), the passband characteristics of the filter 2 are adjusted, and the amplifier 7 is operated to transmit a carrier wave signal of a required level from the antenna 1. On the other hand, when no transmission is performed, the control signal supplied to the input terminal 8 causes
The passband characteristics of the filter 2 are switched so as to be tuned to the signal frequency (FR) transmitted from the master station, and the operation of the amplifier 7 is stopped to lower the carrier wave level. Therefore, this slave station is supplied with the control signal and performs transmission for a predetermined allotted time, and the level is lowered outside of that transmission time to enable transmission from other slave stations (not shown). There is. Figure 2 shows how the filter 2 is controlled by the above control signal.
During transmission and reception, the passband characteristics of are switched like A and B, and the carrier wave signal level rises during transmission (
Ls), its level decreases except when transmitting (LR)
This is an explanatory diagram showing the situation. Therefore, in combination with the on/off operation of the amplifier 7, it is possible to effectively obtain a large amount of attenuation that can prevent signal interference, especially between slave stations. As described above, the present invention provides a gearing device in which a master station obtains different data of the same carrier wave from a plurality of slave stations, in which the transmission frequency or the passband of the reception frequency of the filter is switched by a control signal for transmission/reception switching, and By lowering the gain of the amplifier connected to the local oscillator during reception, and increasing the gain of the amplifier during transmission, the local oscillation frequency signal modulated by the transmission data is amplified and transmitted through the above filter. Since only two frequencies are used, a simple system can transmit information from many slave stations and from the master station, and the oscillation circuit of the slave stations operates continuously, resulting in improved frequency stability. Excellent, high-speed and reliable transmission.

Furthermore, since the oscillation frequency on the slave station side is the same, it is easy to prepare a large number of devices, and a data gathering device with a simple configuration and low cost can be widely provided on the market.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a block circuit diagram of a slave station for time-division multiplex data gathering, and FIG. 2 shows the passband characteristics of a filter. 1...Antenna, 2...Filter, 3
......High frequency amplifier, 4...Local oscillation circuit, 5...Mixing circuit, 7...Amplifier,
8... Control signal input terminal.

Claims (1)

[Claims] 1 In a gearing device in which a master station obtains different data on the same carrier wave from multiple slave stations, the transmission frequency or reception frequency passband of the filter is switched using a control signal for transmission/reception switching, and at the time of reception, the gearing device is connected to a local oscillator. A child of a time-division multiplex data gearing device that lowers the gain of the amplifier, increases the gain of the amplifier during transmission, amplifies the local oscillation frequency signal modulated by the transmitted data, and transmits it through the above filter. Bureau.