JPH02298128A - Radio telephone system - Google Patents

Abstract

PURPOSE:To attain low cost, small size and light weight by detecting a received signal strength level while a master set and a slave set of a radio telephone set are in communication and resetting the channel of a radio frequency of the radio telephone set when the received signal strength level is lower than the prescribed level. CONSTITUTION:A radio telephone system is constituted of a master set 1 connected to a wire telephone line 3 and a slave set 35 connected to the radio line of the master set 1. A signal is received by a receiver 16 via a receiving antenna 15 from a slave set 35 to the master set 1. In this case, the signal revived by the receiver 16 detects the received signal strength level by a received signal strength level detection circuit 22 and whether or not the level is lower than a value such as 0dBmuV for the prescribed time (t1sec) is discriminated by a control circuit 24 and when the level is lower than 0dBmuV for the prescribed time, the control circuit 24 discriminates that the PLL of a synthesizer is in unlocked state to control the PLL IC 30 of the synthesizer 33 and to revise the oscillating frequency of the synthesizer 33, thereby applying the result to the receiver 16 or the transmitter 19 and resetting the channel of the radio frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Field of Industrial Application) The present invention relates to a radiotelephone device, and more particularly to a radiotelephone device that reconfigures a radio frequency channel.

(Prior Art) FIG. 4 is a block diagram of a conventional wireless telephone device. This wireless telephone device includes a base unit 1 connected to a wired telephone line 3;
It is configured to include this base unit 1 and a slave unit 2 connected via a wireless line.

In FIG. 4, the base unit 1 includes a line relay 4, a hybrid circuit 5, a transmitter 6, a transmitting antenna 7, a receiving antenna 8,
Receiver 9, synthesizer 10, received electric field level detector 1
1, ID code detector 12, control circuit 13, memory 14
The handset 2 is equipped with a receiving antenna 15 and a receiver 16.
, receiver 17, transmitter 18, transmitter 19, transmitting antenna 20. synthesizer 21, received electric field level detector 22,
ID code detector 23, control circuit 24, sounder 25,
It includes a liquid crystal display (LCD) 26 and a key unit 27. Note that the base unit 1 has a call receiving means (not shown), and when receiving a call signal via the wired telephone line 3, the line relay 4. is set to turn on.

FIG. 5 shows the synthesizer 21 of the handset 2 in more detail and the control and one-way (CONT) 24 of the handset 2.

In FIG. 5, the synthesizer 21 is a PLL (Phase
dLocked Loop) Consists of a PLLIC 30 which is an IC between the synthesizers, a crystal oscillator 32 that generates a reference frequency, a voltage controlled oscillator (VCO) 31, a low pass filter 34 and a comparator 35.
, voltage controlled oscillator 31 , PLLIC 30 and control circuit 24
generates a variable frequency. Further, the PLLIC 30 outputs signals as shown in FIGS. 6(a) and 6(b) when the PLL is in the locked state and in the unlocked state, respectively. In the output of this PLLIC 30, when the signal (a) in the locked state is passed through the low-pass filter 34, the DC component disappears, and when the signal (b) in the unlocked state is passed through the low-pass filter 34, the DC component remains. . A comparator 35 inputting the signals passed through these low-pass filters 34 determines the level of the DC component and outputs a signal to the control circuit 24 indicating whether the PLL is in a locked state or an unlocked state.

Based on the above, the sequence operation of the base unit 1 and handset 2 will be explained below with reference to the oscillation sequence diagram from the handset 2 to the base unit 1 of the wireless telephone device shown in FIG.

Off-hook the handset 2 and connect the transmitter 19 and transmitting antenna 20.
A calling signal is transmitted to base unit 1 via. This signal is received by the receiver 19 via the receiving antenna 8 of the base unit 1. The base unit 1 checks the ID included in the calling signal with the ID detection circuit 12, and if they match, sends a call response signal including a channel designation signal to the transmitting antenna 7 to the slave unit. Send to 2. The handset 2 receives the call response signal with the receiver 16, detects the ID code included in the call response signal with the ID code detection circuit 23, and checks whether or not they match. Further, the reception electric field level detection circuit 22 determines whether the specified channel is an empty channel or not, and if the ID codes match and the specified channel is empty, a channel switching completion signal is sent to the base unit. Send to. As a result, the control circuit 13 of the base unit 1 turns on the line relay 4, connects the hybrid circuit 5 and the wired telephone line 3, and turns on the audio circuit of the slave unit 2. Furthermore, if the 10 codes do not match, or if the designated channel is not available, the handset 2 stops operating and returns to the standby state. Furthermore, after the audio circuit is turned on and the call state is established, if handset 2 goes on-hook and disconnects the audio circuit to base unit 1, a call termination signal is sent to base unit l, and base unit 1 also connects to the slave unit. Disconnect the audio circuit to machine 2.

All of the signal exchanges in the transmission sequence diagram of FIG. 7 described above cannot be performed unless the PLL of the synthesizer 21 of the handset 2 is in the locked state. For example, when transmitting a call signal to base unit 1,
If the PLL is out of lock, the master s1 cannot receive the signal, and even if it does, the slave cannot receive the data sent from the master. When the PLL becomes unlocked, the base device 1 and the slave device 2 stop operating, and enter a standby state after a certain period of time has elapsed. Therefore, unnecessary waves are not generated for a long time.

Now, with reference to the flowchart shown in FIG. 8, the operation when the wireless telephone device is in a talking state will be described.

Handset 2 of the wireless telephone device receives a signal from base unit 1 via receiving antenna 15 at receiver 16 . At this time, receiver 1
The signal received at step 6 is applied to the received electric field level detection circuit 22, which detects the received electric field level and determines whether the received electric field level has fallen below a certain value for a certain period of time (step 21). When the received electric field level drops to 7, the control circuit 24 causes the sounder 25 to sound an alarm (ALARM) (step 27). If the received electric field level continues to drop for a certain period of time (step 22), the control device 24 performs call termination processing under predetermined control (step 26) and enters a standby state. If it does not decrease further for a certain period of time in step 22, the control circuit 24
is the P of the synthesizer 21 as described above in FIG.
PLLIC30 determines whether LL is in an unlocked state.
However, it is judged from the signal passed through the low-pass filter 34 and the comparator 35 (step 23), and if the lock is off, the radio frequency channel is re-fixed (step 28), and the process moves to step 24. If the lock is not released in the step knob 23, the process moves to the step knob 24, and it is determined whether there is a key input from the key unit 27 (step 24), and if there is, the key input data is transferred to the base unit 1. When the message is sent (step 29), the process moves to step 25. If there is no key manpower in step 24, step 2
Move to 5. In step 25, it is determined whether the story has ended (
Step 25), and if the call has ended, a call end process is performed (step 26), and the device enters a standby state. It is determined whether or not the call has ended (step 25), and if the call has not ended, the process returns to step knob 21.

(Problems to be Solved by the Invention) As mentioned above, in the conventional device, the P[, LI
By applying a signal from C through a low-pass filter and a comparator to the control circuit, the PL of the synthesizer is controlled.
Because L was detected to be unlocked, the price increased accordingly. The present invention has been made in view of this problem, and an object of the present invention is to provide a wireless telephone device that is inexpensive, compact, and lightweight.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a wireless telephone device including a base unit connected to a wired line and a slave unit connected to the base unit via a wireless line. and detecting means for detecting a received electric field level during a call, and means for resetting the radio frequency channel of the wireless telephone when the output level of the detecting means falls below a predetermined level. It is characterized by

(Function) In the present invention, during a call between the base unit and the slave unit of the wireless telephone device,
The received electric field level is detected, and if the received electric field level falls below a predetermined level, the radio frequency channel of the wireless telephone is reset.

(Embodiment) An embodiment of the wireless telephone device of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the wireless telephone device of the present invention.

In FIG. 1, parts having the same functions as those of the conventional wireless telephone device shown in FIG. 4 are given the same numbers, and detailed explanations of their operations will be omitted.

The wireless telephone system is composed of a base unit 1 connected to a wired telephone line 3 and a slave unit 35 connected to the base unit 1 wireless line, and the base unit 1 includes a line relay 4, a hybrid circuit 5, and a transmitter. machine 6, transmitting antenna 7, receiving antenna 8
, receiver 9, synthesizer 10, received electric field level detector 11, ID code detector 12, control circuit 13, memory 1
4, the handset 35 includes a receiving antenna 15, a receiver 16, a handset 17, a transmitter 18, a transmitter 19, a transmitting antenna 20, a synthesizer 33, and a received electric field level detector 2.
2, ID code detector 23, control circuit 24, sounder 2
5, a liquid crystal display (LCD) 26 and a key unit 27. The line relay 4 of the base unit 1 has a call receiving means (not shown), and when it receives a call signal via the wireless telephone line 3, the line relay 4 is turned on.

FIG. 2 shows the synthesizer 3 of the handset 35 of the wireless telephone device.
3 and the control circuit 24 in more detail.

In FIG. 2, the synthesizer 33 is a PLL (Phase
The device includes a PLLIC 30 which is an IC for a dLocked Loop synthesizer, a crystal oscillator 32 that generates a reference frequency, and a voltage controlled oscillator (VCO) 31. On top of this configuration, a control circuit 24 is further provided with PLIjC3.
By controlling 0, a stable and variable frequency can be generated.

FIG. 3 is a flowchart showing operations during a call between handset 35 and base unit 1 of the wireless telephone device. This flowchart is shown in FIG. 7, and in the described transmission sequence diagram, the base unit 1 receives the channel switching completion signal from the slave unit 35.
This figure shows the operation during a phone call after turning on the audio circuit.

Note that the oscillation sequence of this embodiment is the same as that of the conventional one, and its explanation will be omitted for the sake of convenience.

The operation of the wireless telephone device during a call will be described below according to the flowchart shown in FIG. 1N3.

The slave unit 35 receives a signal from the base unit 1 via the receiving antenna 15 at the receiver 16. At this time, the signal received by the receiver 16 is applied to the received electric field level detection circuit 22, which detects the received electric field level and determines whether the received electric field level falls below a certain value, for example, OdBμV for a certain period of time (1+ seconds). The control circuit 24 determines whether the
1).

If the received electric field level falls below OdBμ for a certain period of time, the control circuit 24 determines that the PLL of the synthesizer is out of lock, and controls the PLLIC 30 of the synthesizer 33 to change the oscillation frequency of the synthesizer 33. In addition to the receiver 16 or transmitter 19, the radio frequency channel is reconfigured (step 36). After resetting, the control circuit 24 receives the detection output of the received electric field detection circuit 22, and the received electric field level is QdBμ again.
It is determined whether or not it is below V (step 37), and if it is below, the control circuit 24 uses the sounder 25 to emit an alarm sound (^
LARM) (step 38), step 32
to move to. Also, in step 31, for a certain period of time (1+ seconds),
If the received electric field level does not decrease, the process moves to step 32. Then, the control circuit 24 determines whether or not the received electric field level has fallen below the received electric field level OdBμV for a further fixed period of time (2 seconds; t+<t2). A call termination process is performed (step 35), and the device enters a standby state. Step 32
If the received electric field level does not decrease for a certain period of time (t2 seconds), it is determined whether or not the key unit 27 of the handset 35 has the key power (step 33). If there is a key input, the key input data is transmitted from the handset 35 to the base unit 1 (step 39), and the process moves to step 34. Step 33
If it is determined that there is no key manpower, the process moves to step 34.

The control circuit 24 determines whether or not the call has ended and proceeds to step (34).
), if the call is over, perform end-of-talk processing (step 35);
The machine enters standby mode. Determine whether or not there is an end to the conversation (step 34)
), if the call is not over, the process returns to step 31.

In the above embodiment, only the synthesizer 33 of the handset 35 has the configuration shown in FIG. 2, and the flowchart shown in FIG. 3 is also a flowchart showing the operation of the handset 35, but the present invention is not limited to this. Instead, the configuration and flowchart of the synthesizer 10 of the base unit 1 may be the same as those of the slave unit 35.

〔Effect of the invention〕

As explained above, in the wireless telephone device of the present invention, the detection circuit detects the level of the received signal, and if the level falls below a predetermined level, the channel is reset. Therefore, since it is not necessary to perform level detection in the synthesizer, the low-pass filter and comparator that connect the PLLIC of the synthesizer and the control circuit can be deleted. Furthermore, this allows the wireless telephone device to be made inexpensive, compact, and lightweight.

[Brief explanation of the drawing]

FIG. 1 is a professional diagram of an embodiment of the radio telephone device of the present invention, FIG. 2 is a detailed diagram of the synthesizer and control circuit of the radio telephone device of the present invention, and FIG. 3 is a diagram of the radio telephone device during a call. A flowchart showing the operation, FIG. 4 is a block diagram of a conventional wireless telephone device, FIG. 5 is a detailed diagram of a synthesizer and a control circuit of the conventional wireless telephone device, and FIG. 6 is a diagram of a PLLIC.
FIG. 7 is a calling sequence diagram of a conventional radio telephone device, and FIG. 8 is a flow chart showing the operation of the conventional radio telephone device during a call. 1... Base unit, 3... Wired telephone line, 4... Line relay, 5... Hybrid circuit, 6, One... Transmitter, 7.20... Transmitting antenna, 8. 15...Receiving antenna, 9.16...Receiver, 10.33...
Synthesizer, 11.22... Reception electric field level detector, 12゜23... ID code detector, 13.24...
・Control circuit, 14...Memory, 17...Telephone receiver, 1
8... Transmitter, 25... Sounder, 26... Liquid crystal display, 27... Key unit, 30... PLLI
C, 31... Voltage controlled oscillator, 32... Crystal oscillator. Figure 3 Figure 4

Claims (1)

[Scope of Claims] In a wireless telephone device comprising a base unit connected to a wired line and a slave unit connected to the base unit via a wireless line, during a call between the base unit and the slave unit, a received electric field is generated. A radiotelephone device comprising: detection means for detecting a level; and means for resetting a radio frequency channel of the radiotelephone when the output level of the detection means falls below a predetermined level. .