JPH0619234Y2 - Telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a telephone having a master unit connected to a telephone line and a slave unit wirelessly communicating with the master unit.

“Prior Art” Conventionally, there is a technology in which a specific transmission frequency (for example, 46 MHz) and a reception frequency (49 MHz) are set and wireless communication is performed between a master unit and a slave unit.

"Problems to be solved by the invention" In the conventional technology, a plurality of bandpass filters are provided between a transmission circuit and an antenna to emit a transmission output from the antenna as a radio wave, and a plurality of bands are provided between the antenna and a reception circuit. Since a filter is provided and the radio waves received by the antenna are input to the receiving circuit, it is not possible to easily reduce the manufacturing cost by installing multiple band filters, and it is not possible to maintain the transmission / reception function by reducing the band filters. There was a functional and functional problem.

"Means for Solving Problems" Therefore, the present invention is provided with the master unit connected to the telephone line and the slave unit wirelessly communicating with the master unit, and the transmission frequency of the transmission circuit and the reception of the reception circuit. In a telephone having different frequencies, a first coupling resonance circuit that forms a tank circuit that resonates at the reception frequency is provided between the transmission circuit and the antenna, and between the reception circuit and the first coupling resonance circuit, A second coupled resonance circuit is provided to form a trap circuit whose impedance is set to zero at the transmission frequency.

[Operation] Therefore, according to the present invention, when different frequencies are received by the antenna, the transmission circuit side is made to have a high impedance when viewed from the antenna so that the reception signal is not input to the transmission circuit side, while the transmission signal is transmitted. During transmission of a transmission signal from a circuit through an antenna, this transmission signal is prevented from being input to the reception circuit, that is, the signal output from the transmission circuit is the tank circuit of the first coupling resonance circuit that resonates at the reception frequency. The tank circuit is connected to the trap circuit of the second coupled resonant circuit whose impedance is set to zero at the transmission frequency. Therefore, the secondary current at the entrance of the reception circuit is the maximum at the reception frequency. And becomes the lowest at the transmission frequency. Therefore, the transmitted signal is released to the ground before being input to the receiving circuit.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. First
The figure is a communication circuit diagram, and Fig. 2 is an overall illustration.
(1) is a master unit, which is connected to the telephone line (2) to input drive power (DC 9V) and charging terminal (3)
A cradle (5) having (4) and a transmitting / receiving antenna (6) are provided.

Further, in the figure, (7) is a slave unit, and the transmitter (8) and the receiver (9)
And a dial operation unit (10) and a transmitting / receiving antenna (11).

Further, the communication circuit of FIG. 1 is incorporated into both the master unit (1) and the slave unit (7), and the transmitting / receiving antenna (6) (1
It is provided with a transmission circuit (12) and a reception circuit (13) connected to 1).

A first coupled resonance circuit (14) is provided between the transmission circuit (12) and the antennas (6) and (11), and a primary coil (15) connected to the output side of the transmission circuit (12), A secondary coil (16) having one end connected to the antennas (6) and (11) and a capacitor (17) connected in parallel to the secondary coil (16) are connected to the first coupled resonance circuit (14). In order to form a tank circuit by the transmission output from the transmission circuit (12), each coil (1
5) The inductance of the (16) and the capacity of the capacitor (17) are set, and the transmission output is converted into radio waves by the antennas (6) and (11) and emitted.

Further, a second coupling resonance circuit (18) is provided between the receiving circuit (13) and the first coupling resonance circuit (14), and a positive winding coil (19) as a primary side coil and the secondary side coil are provided. Reverse winding coil (20) provided in parallel with the forward winding coil (19) to be connected to the coil (16)
And a secondary coil (21) and a capacitor (22) connected in series to the secondary coil (21) in the second coupling resonant circuit (18), and each coil (19) (20) (21) and Capacitor (22)
To form a tank circuit and the secondary coil (21) and capacitor (22) to form a trap circuit.
0) Set the inductance of (21) and the capacity of capacitor (22).

Then, the forward winding coil (19) and the secondary coil (21) are connected to connect this connection part to the input side of the receiving circuit (13), and the radio waves received by the antennas (6) and (11) are received and input. At the same time, by the symmetrically wound positive winding coil (19) and reverse winding coil (20) having substantially the same strength in the opposite direction, the second coupled resonance circuit (1
8) It is configured to absorb and attenuate the leaked transmission output.

Further, as shown in FIG. 3, a wiring board (23) for forming the receiving circuit (13) and the like is provided, and a winding frame (24) made of glass or bakelite is fixed to the wiring board (23).
The secondary coil (21) of the second coupling resonance circuit (18) is wound around the winding frame (24) closest to the wiring board (23), and the first coupling resonance circuit (14) and the secondary side are wound. The forward winding coil (19) connected between the coils (21) is wound around the winding frame (24) position farthest from the wiring board (23), and the forward winding coil (19) and the secondary coil (21) The reverse winding coil (20) is wound around the position of the winding frame (24), and the coils (19), (20) and (21) are wound around the same winding frame (24).

This embodiment is configured as described above, and when the transmission frequency of the transmission circuit (12) is set to 46 MHz, as shown in FIG. 4, the output of the secondary coil (16) of the first coupled resonance circuit (14). The maximum frequency characteristic of is at 46 MHZ, and when the receiving frequency of the receiving circuit (13) is 49 MHZ, the frequency characteristic of the secondary side output of the second coupling resonant circuit (18) is as shown in FIG. , 49
Maximum at MHZ, minimum at 46 MHZ. Then, the transmission output from the transmission circuit (12) is emitted as a radio wave from the antennas (6) and (11) via the first coupling resonance circuit (14), and the impedance of the first coupling resonance circuit (14) is changed. , Is set to be significantly higher than that of the second coupling resonance circuit (18), so that the transmission is performed without being affected by the second coupling resonance circuit (18).

The radio waves received by the antennas (6) and (11) are received and input through the second coupling resonance circuit (18), and the transmission output leaking to the second coupling resonance circuit (18) is The reverse inductance of the reverse winding coil (20) and the reverse winding coil (20) cancel each other out to absorb and attenuate them.

The primary side coil (15) and the secondary side coil (16) of the first coupled resonant circuit (14) are wound around the same winding frame and attached to the wiring board.

"Effect of the invention" As is apparent from the above embodiments, the present invention is a telephone line (2)
A master unit (1) connected to the master unit and a slave unit (7) wirelessly communicating with the master unit (1), and the transmission frequency of the transmitter circuit (12) and the receiver circuit.
In a telephone having a reception frequency different from that of (13), a first coupling resonance circuit (14) forming a tank circuit resonating at the reception frequency between the transmission circuit (12) and the antennas (6) and (11). And a receiving circuit (13) and the first coupling resonant circuit (1
A second coupled resonant circuit that forms a trap circuit with impedance set to zero at the transmission frequency between 4)
By providing (18), it is not necessary to provide a plurality of band-pass filters to maintain the transmission / reception function as in the conventional case, and it is possible to easily reduce the manufacturing cost and maintain the transmission / reception function as compared with the conventional case. It has a great effect.

[Brief description of drawings]

FIG. 1 is a communication circuit diagram showing an embodiment of the present invention, FIG. 2 is an overall explanatory diagram, FIG. 3 is a partial diagram, and FIGS. 4 and 5 are output diagrams. (1) ... Main unit (2) ... Telephone line (6) (11) ... Transmission / reception antenna (7) ... Slave unit (12) ... Transmission circuit (13) ... Reception circuit (14) ... First coupled resonant circuit ( 18) ... Second coupled resonant circuit (19) ... Normal winding coil (20) ... Inverse winding coil (21) ... Secondary coil (23) ... Wiring board (24) ... Winding frame

Claims (1)

[Scope of utility model registration request] 1. A master unit (1) connected to a telephone line (2) and a master unit
(1) and a slave unit (7) for wireless communication with the transmitter circuit (1
In a telephone in which the transmission frequency of 2) and the reception frequency of the reception circuit (13) are different, the transmission circuit (12) and antenna (6) (11)
A first coupling resonant circuit (14) forming a tank circuit resonating at the receiving frequency is provided between the receiving circuit and the receiving circuit (13).
A telephone set characterized in that a second coupling resonance circuit (18) forming a trap circuit whose impedance is set to zero at a transmission frequency is provided between the first coupling resonance circuit (14) and the first coupling resonance circuit (14).