JPH07260925A - Transceiver device - Google Patents

Abstract

PURPOSE:To reduce the attenuation of an input signal. CONSTITUTION:The primary side of a matching transformer 3 is shortcircuited on the operation of a selector switch 6 such as a relay switch during the receiving operation of a transceiver 4. Inductance viewed from the secondary side of the transformer 3 is thereby made zero and the attenuation of 6 high frequency input signal is eliminated. Also, the shortcircuit of the switch 6 is released at the time of transmitting operation. As a result, the attenuation of the input signal can be prevented, and a drop in signal-nose ratio due to a nose from a transmitter 2 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver, and more particularly to a transmitter / receiver which emits sound waves into water and receives sound waves from water.

[0002]

2. Description of the Related Art Generally, a sonar (SONAR, soun) is used.
In d navigation and ranging, a wave transmitter and a wave receiver including a piezoelectric vibrator are used. A wave transmitter is used to radiate sound waves into water, and a wave receiver is used to receive sound waves in water.
With this, seafloor sounding and fish detection are performed.

Conventionally, in an active sonar device, a wave transmitter that radiates a sound wave in water and a wave receiver that receives a sound in water are commonly used, and are used as a wave transmitter / receiver. This transmitter / receiver requires control for switching between a signal for transmission and a signal for reception.

This switching control will be described with reference to FIG. In the case of transmitting waves in FIG. 3, the output of the transmitter 2 which receives 20 of the transmission signal is input to the primary side of the matching transformer 3. Then, the secondary-side inductance component of the matching transformer 3 and the capacitance component 41 of the wave transmitter / receiver 4 are caused to resonate, power loss is reduced, and the wave is transmitted to the wave transmitter / receiver 4, whereby efficient wave transmission is performed. At the time of transmission, a large voltage appears on the secondary side of the matching transformer 3, but the protection diode 1 connected in parallel to the signal line is made conductive by the transmission signal and the receiver 5 is protected.

The received signal at the time of wave reception passes through the secondary side of the matching transformer 3 which is connected in series with the wave transmitter / receiver 4. Therefore, the high-frequency received signal is attenuated by the inductance seen from the secondary side of the matching transformer 3 and the stray capacitance due to the PN junction of the diode 1 before being input to the receiver 5. In addition, 50 is a received signal.

That is, as shown in FIG. 3, in the diode 1, since two diodes are connected in opposite directions and are connected in parallel to the signal line, the stray capacitance due to the PN junction is doubled. Therefore, by the inductance seen from the secondary side of the diode 1 and the transformer 3,
The received signal will be attenuated.

Here, the voltage received by the transmitter / receiver 4 is represented by ei
, Zi is the input impedance of the receiver 5, V0 is the input voltage of the receiver 5, and L is the inductance seen from the secondary side of the transformer 3, then V0 = ei * Zi / (Z + Zi) (1). However, impedance Z = 2πfL (f is the frequency of the received signal). Therefore, according to the equation (1), the attenuation amount ei -V0 is ei -V0 = ei * {1-Zi / (Z + Zi)} (2).

Therefore, from the equation (2), when Zi is constant, the larger the impedance Z, the larger the attenuation amount.

[0009]

The inductance seen from the secondary side of the transformer 3 is a large value because it is connected in series to the receiver and the transmitter 2 connected to the primary side can be seen as a load as it is. . Therefore, the diode 1 connected in parallel with the inductance L and the signal line
Due to the stray capacitance due to the PN junction, there is a drawback that a high-frequency received signal at the time of reception is greatly attenuated.

A technique for improving the characteristics of a transformer is disclosed in Japanese Patent Laid-Open No. 62-293892, but the amount of attenuation cannot be reduced by using such a technique.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object thereof is to provide a transmitting / receiving apparatus in which the amount of attenuation of a received signal is small.

[0012]

A transmitting / receiving apparatus according to the present invention comprises a transformer for transmitting a transmission signal output from the transmission means and input to the primary side to a transducer, and a transformer for transmitting the transmission signal to the outside and externally. And a short-circuiting means for short-circuiting the primary side of the transformer at the time of reception by the receiving means.

[0013]

[Function] The primary side of the transformer is short-circuited during reception by the wave transmitter / receiver. As a result, the inductance seen from the secondary side of the transformer is made zero, and the attenuation of the high frequency received signal is eliminated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a transmitting / receiving apparatus according to the present invention, and the same portions as those in FIG. 3 are designated by the same reference numerals. In the figure, the transmitting device according to the embodiment of the present invention is different from the conventional one in that a switching circuit 7 including a diode 1 is added. And
A changeover switch 6 for short-circuiting a signal line connecting the output of the transmitter 2 and the primary side of the transformer 3 is provided in the changeover circuit 7.

As shown in FIG. 2, the changeover switch 6 is controlled by a CPU (not shown) so that it is turned on (closed state) during a receiving operation and turned off (opening state) during a transmitting operation. A well-known relay switch, for example, is used as the change-over switch 6, and is given a predetermined voltage under the control of a CPU (not shown) to be turned on at the time of reception operation and OF at the time of transmission operation.
It is controlled by F. That is, the switch 6 is short-circuited during the reception operation and released during the transmission operation.

Returning to FIG. 1, the transmission signal input to this apparatus at the time of transmission is power-amplified by the transmitter 2 and input to the primary side of the matching transformer 3. The signal input to the primary side of the matching transformer 3 resonates in parallel due to the secondary-side inductance component of the matching transformer 3 and the capacitance component of the transducer 4 so that power can be efficiently supplied to the transducer 4. Add. This electric signal is converted into an acoustic signal by the wave transmitter / receiver 4 and transmitted to the outside.

On the other hand, the received signal at the time of wave reception passes through the secondary side of the matching transformer 3 which is connected in series with the wave transmitter / receiver 4. The secondary side inductance of the matching transformer 3 becomes zero because the primary side of the transformer 3 is short-circuited by the changeover switch 6. Therefore, the received signal that has passed through the secondary side of the matching transformer 3 is input to the receiver 5 without the high frequency signal being attenuated by the stray capacitance of the PN junction of the diode 1. Further, by short-circuiting the output of the transmitter 2 with the changeover switch 6, it is possible to reduce high-frequency noise of the power source in the transmitter 2 and external noise from the transmission signal input.

It is also conceivable that another switch is provided in place of the diode 1 so that the diode 1 is turned on during reception and turned off during transmission. That is, in addition to the change-over switch 6 in FIG. 1, a change-over switch is provided in the diode 1 part so that one of these two switches is turned on and the other is turned off.

The wave transmitting / receiving apparatus of the present embodiment configured as described above can transmit a sound wave corresponding to the transmission signal into the water and can obtain a reception signal corresponding to the sound wave from the water, and the reception signal. Therefore, there is no attenuation and the signal can be received efficiently. It is obvious that the present invention can be widely applied to not only the transmitting / receiving device used for the sonar but also the transmitting / receiving device having the transformer. Further, the changeover switch is not limited to the relay switch described above, and various kinds of switches can be used.

[0021]

As described above, according to the present invention, by short-circuiting the primary side of the matching transformer during the receiving operation, the inductance of the secondary side of the transformer can be made zero and the high frequency signal is attenuated. The effect is that you can receive without doing. In addition, by short-circuiting the output of the transmitter, it is possible to prevent deterioration of the SN ratio at the reception signal output end due to high frequency noise of the transmission power source and external noise from the transmission signal input.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a transmission / reception device according to an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the changeover switch shown in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional transmission / reception device.

[Explanation of symbols]

 1 Protective diode 2 Transmitter 3 Transformer 4 Transducer 5 Receiver 6 Changeover switch

Claims (4)

[Claims] 1. A transformer for transmitting a transmission signal output from a transmission means and input to a primary side to a wave transceiver, and a transformer for transmitting the transmission signal to the outside and receiving a reception signal from the outside on the secondary side of the transformer. A transmission / reception device comprising: a wave transmitter / receiver for inputting to the receiving means via the terminal; and a short-circuit means for short-circuiting the primary side of the transformer when the receiving means receives the wave. 2. The transmitter / receiver transmits a sound wave according to the transmission signal into the water and inputs a reception signal according to the sound wave from the water to the receiving means via the secondary side of the transformer. The transmitter / receiver according to claim 1, which is characterized in that. 3. The transmitter / receiver according to claim 1, wherein the short-circuiting means releases the short-circuit when the transmission signal is output by the transmitting means. 4. The transmitter / receiver according to claim 1, wherein the short-circuit means is a relay switch.