JPH05129979A - Radio transmitter - Google Patents

Abstract

PURPOSE:To extend a communication available distance by providing a limit means limiting a transmission power with a signal from a transmission means and a control means stopping the operation of the limit means for a prescribed time to the transmitter so as to set a maximum transmission output state for a prescribed time. CONSTITUTION:In the transmission state with transmission equipment changeover switches 10a, 10b thrown to the position of a contact (b), when a switch 14 is closed, a DC voltage is applied to a timer circuit 12 and a switch 13 is open for a prescribed time. Thus, a control signal from a transmission output limit device 9 is not sent to a power amplifier 3, a limit function of the transmission power is not operated and the amplifier 3 reaches a maximum transmission output state for a prescribed time. When the switch 14 is opened while the circuit 12 counts time, the circuit 12 outputs a control signal used to turn on the switch 13 and a limit operation by the limit device 9 is restarted. Thus, the operation of the limit means is tentatively stopped to obtain the maximum transmission output state thereby extending the communication available distance.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a wireless transmitter for wireless communication.

[0002]

2. Description of the Related Art In recent years, wireless communication devices have begun to spread not only for business use but also for general use and consumer use, and are also widely used for leisure and sports.

FIG. 2 is a block diagram of a conventional wireless communication device. In FIG. 2, the voice spoken to the microphone 1 is converted into a voice signal by the microphone 1 and then input to the FM modulator 2. The FM modulator 2 is
After frequency-modulating a carrier wave of a predetermined high frequency according to an input audio signal, the modulated signal after modulation is supplied to the power amplifier 3
Output to. The power amplifier 3 converts the input modulated signal into
The transmission signal after amplification is amplified to a predetermined rated transmission power with an amplification degree corresponding to an output control signal output from a transmission output limiter 9 described later, and then the transmission / reception changeover switch 1
It is output to the antenna 4 through the contact b of 0b and its common terminal c, and is radiated as a radio wave from the antenna 4 and is also output to the transmission output limiter 9.

Here, the transmission output limiter 9 reduces the amplification degree of the power amplifier 3 when the power of the transmission signal output from the power amplifier 3 becomes larger than the rated transmission power, while the transmission signal is reduced. When the power of the power amplifier 3 becomes smaller than the rated transmission power, the amplification degree of the power amplifier 3 is increased so that the power amplifier 3 always outputs the transmission signal of the rated transmission power. An output control signal for controlling the power amplifier 3 by limiting the transmission output power from the output state is output to the power amplifier 3. For example, when the rated transmission power is set to 5 W, the power amplifier 3 having a maximum output power of 10 W is used, and the power amplifier 3 uses the output control signal output from the transmission power limiter 9 to output the transmission signal. The method of limiting the power to 5 W is generally used. This is to obtain stable rated transmission power continuously for a long time.

On the other hand, the high frequency received signal received by the antenna 4 is input to the frequency converter 6 via the high frequency amplifier 5. The frequency converter 6 converts the input reception signal into an intermediate frequency signal and then outputs it to the FM demodulator 7. The FM demodulator 7 FM demodulates the input intermediate frequency signal into a low frequency signal, and then outputs the low frequency signal to the speaker 8.

The negative electrode of the DC power supply 11 which is a voltage source for outputting a predetermined DC voltage is connected to the ground, and the positive electrode thereof is connected to the FM modulator 2 and the power amplifier via the common terminal c of the transmission / reception changeover switch 10a and its contact b. 3 and transmission output limiter 9
And a transmission / reception changeover switch 10a.
Is connected to the high-frequency amplifier 5, the frequency converter 6, and the FM demodulator 7 via the common terminal c and its contact a. In addition,
The transmission / reception changeover switches 10a and 10b are PTT switches (not shown) provided in the microphone 1, for example.
When is not pressed, the contact is switched to the contact a, while when the PTT switch is pressed, it is switched to the contact b.

In the wireless communication device configured as described above, first, at the time of reception when the operator does not press the PTT switch, the common terminal c of each of the transmission / reception changeover switches 10a and 10b is connected to the contact point a. The output voltage of the power supply is the high frequency amplifier 5, the frequency converter 6, and the FM demodulator 7.
Is applied to the wireless communication device and the wireless communication device is in the reception state. On the other hand, at the time of transmission when the operator presses the PTT switch, since the common terminal c of each of the transmission / reception changeover switches 10a and 10b is connected to the contact b, the output voltage of the DC power source is transmitted to the FM modulator 2 and the power amplifier 3. When applied to the output limiter 9, the wireless communication device is in a transmission state.

[0008]

However, in the above-described conventional wireless communication device, at the time of transmission, the power of the transmission signal output from the power amplifier 3 by the transmission output limiter 9 is always a predetermined rated transmission power. Since it is limited to, it is not possible to obtain a transmission power equal to or higher than the preset rated transmission power, and for example, during communication, when the electric field strength of the incoming radio wave to the other station drops to the communication limit level,
At that time, there was a problem that communication had to be terminated.

The object of the present invention is to solve the above problems and to temporarily release the operation of the transmission output limiter to put the transmission power amplifier in the maximum transmission output state and temporarily extend the communicable distance. It is to provide a transmitter.

[0010]

In order to solve the above-mentioned problems, a wireless transmitter according to claim 1 of the present invention has a transmitting means for wirelessly transmitting a transmission signal and a wireless transmission from the transmitting means. The present invention is characterized by comprising limiting means for limiting the power of the transmission signal to a predetermined value based on the transmission signal, and control means for stopping or suppressing the operation of the limiting means for a required time.

A radio transmitter according to a second aspect is the radio transmitter according to the first aspect, further comprising a transmission instructing means for instructing to operate the transmitting means, and the control means includes the transmission. From the time when the operation of the transmitting means is instructed by the instruction means to the time measuring means, and from the time when the operation of the transmitting means is instructed by the transmission instructing means until the time is measured by the predetermined time by the time measuring means An operation control means for stopping or suppressing the operation of the limiting means is provided.

Further, the radio transmitter according to claim 3 is the radio transmitter according to claim 1, further comprising a transmission instruction means for instructing to operate the transmission means, and the transmission means by the transmission instruction means. Selection means for selecting whether or not to start the operation of the control means when the operation of the control means is instructed, and the control means is selected by the selection means to start the operation of the control means. The operation of the limiting means is stopped until the operation of the control means is selected by the selecting means from the time when the operation of the control means is started until the time of the predetermined time is elapsed by the time measuring means. Alternatively, it is provided with an operation control means for suppressing.

Furthermore, the radio transmitter according to claim 4 is the radio transmitter according to claim 2 or 3, further comprising stop instruction means for instructing to stop the operation of the operation control means during operation. The control means further comprises a stop means for stopping the operation of the operation control means when the stop instruction means gives an instruction to stop the operation of the operation control means during operation. ..

[0014]

In the radio transmitter according to claim 1, the limiting means limits the power of the transmission signal to a predetermined value based on the transmission signal wirelessly transmitted from the transmission means, and the control means is required. The operation of the limiting means is stopped or suppressed during the time. Therefore, the operation of the limiting means is temporarily stopped, whereby the transmitting means is in the predetermined maximum transmission output state for the predetermined time and the communicable distance can be temporarily extended. Further, for example, when the power supply for supplying power to the transmitting means is a battery, the time of the maximum transmission output state is limited to the required time by the control means, so that the power is supplied from the battery to the transmitting means. It is possible to limit the amount of power consumed by the wireless communication device, which allows the wireless transmitter to be used for a longer period of time as compared with the case where the control unit does not limit the amount of power consumed.

Further, in the wireless transmitter according to the present invention, the time measuring means measures a predetermined time from the time when the operation of the transmitting means is instructed by the transmission instructing means,
The operation control means stops or suppresses the operation of the limiting means from when the operation of the transmitting means is instructed by the transmission instructing means to when the time measuring means measures the predetermined time. Therefore, the operation of the limiting means can be stopped or suppressed for the predetermined time from when the wireless transmitter is in the transmission state.

Further, in the wireless transmitter according to the present invention, the time measuring means measures a predetermined time from when the selecting means starts the operation of the control means, and the operation control means. Stops or suppresses the operation of the limiting means from when the operation of the control means is selected by the selecting means until the time of the predetermined time is measured by the time measuring means. The operation of the limiting means can be stopped or suppressed for the predetermined time period from the time when the selecting means starts the operation of the control means after the wireless transmitter is in the transmission state.

Further, in the radio transmitter according to the fourth aspect, the stop means of the operation control means is operated when the stop instruction means gives an instruction to stop the operation of the operation control means during operation. Stop the operation. Therefore, even when the operation control means is operating, the operation of the operation control means can be stopped midway using the stop instruction means.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wireless communication device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a wireless communication device of this embodiment.

The radio communication device of this embodiment shown in FIG.
As is clear from comparison with the wireless communication device of the conventional example shown in FIG. 2, the switch 13 which is inserted into the signal path of the output control signal output from the transmission output limiter 9 to the power amplifier 3 and is normally in the on state. And a timer for outputting a switch control signal for turning off the switch 13 when the timekeeping is started by turning on the switch 14 in the transmission state, and then outputting a switch control signal for turning on the switch 13 when a predetermined time is timed And a circuit 12. Hereinafter, the difference will be described in detail.
In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals, and the switches 10a, 10b, 13 and 14 respectively indicate the switching positions in the normal state.

In FIG. 1, a transmission / reception changeover switch 10
The contact b of a is connected to the power supply terminal of the timer circuit 12 and is also connected to the signal input terminal of the timer circuit 12 via the switch 14 which is normally in the off state. The timer circuit 12 starts clocking when a predetermined DC voltage from the DC power supply 11 is applied to its input signal terminal, and outputs a switch control signal for turning off the switch 13 at this time to a control signal terminal of the switch 13. Then, when a predetermined time is measured, a switch control signal for turning on the switch 13 is similarly output.

In the wireless communication device of this embodiment configured as described above, the transmission / reception changeover switches 10a, 10
When the switch 14 is off in the transmission state in which b is interlocked and switched to the contact b, the timer circuit 1
Since the predetermined DC voltage is not applied to the signal input terminal of No. 2, the switch 13 remains in the ON state. This state is exactly the same as the transmission state of the conventional example, the transmission output limiter 9 is in the operating state, and the power output is limited. The power of the transmission signal output from the amplifier 3 is limited to the rated transmission power of 5 W, for example.

Next, the case where the switch 14 is turned on will be described. When the PTT switch is pressed in this state to put it in the transmission state, since the switch 14 is in the ON state, a predetermined DC voltage is applied to the signal input terminal of the timer circuit 12, and the switch 1 is operated for a predetermined time from the start of transmission.
3 is turned off. Therefore, the output control signal output from the transmission output limiter 9 is not transmitted to the power amplifier 3, the function of limiting the transmission signal power does not operate, and the power amplifier 3
Is in the maximum transmission output state in which a transmission signal of, for example, 10 W is output during the above predetermined time.

When the switch 14 is turned on in the transmission state in which the PTT switch is pressed, the switch 14 is turned on.
The power amplifier 3 is in the maximum transmission output state in the same manner as described above for the predetermined time from when the switch is turned on.

When the switch 14 is turned off while the timer circuit 12 is timing, the timer circuit 12 outputs a switch control signal for turning the switch 13 on, whereby the transmission output limiter 9 transmits the signal. The signal power limiting operation is restarted.

The time of the maximum transmission output state is limited by the timer circuit 12 because the heat dissipation device of the radio communication device is designed to withstand continuous use at the rated transmission power, and the transmission signal is This is because it cannot withstand continuous use in the maximum transmission output state where the power limitation has been lifted. To withstand continuous use in the maximum transmission output state, it is necessary to install a larger heat dissipation device. This increases the cost of the wireless communication device, and especially in the portable wireless communication device, the shape thereof becomes large, so that the heat dissipation device cannot be made large. However, there is no problem in transmission in the maximum transmission output state in a short time, and it is possible to intermittently perform transmission in the maximum transmission output state by taking a sufficient cooling period or reception period. Further, for example, when the DC power supply 11 is a battery, by limiting the time of the maximum transmission output state by the timer circuit 12, it is possible to limit the amount of power supplied from the battery to the wireless communication device and consumed. As a result, the time period in which the wireless communication device can be used by using the DC power supply 11 of the battery can be extended as compared with the case where the timer circuit 12 does not limit the time.

As described above, according to this embodiment, the switches 13 and 14 and the timer circuit 12 are provided, and the switch 13 is turned on and the switch 14 is turned off. The output control signal to be output is no longer transmitted to the power amplifier 3, and the operation of limiting the transmission signal power by the transmission output limiter 9 can be temporarily stopped. As a result, the power amplifier 3 is in the maximum transmission output state for the above predetermined time, and the communicable distance can be temporarily extended.

In the above embodiment, the switch 13 is turned off for the above predetermined time to temporarily stop the transmission signal power limiting operation by the transmission output limiter 9. However, the present invention is not limited to this. During the above predetermined time, the transmission signal power limiting operation is not completely stopped, but the transmission signal power control operation is suppressed and a transmission signal of 8 W, which is 80% of the maximum output power of the power amplifier 3, is generated. The power amplifier 3 may be controlled to transmit. In this case, switch 13
Is not inserted, the power of the transmission signal output from the power amplifier 3 in response to the switch control signal output from the timer circuit 12 when the timer circuit 12 measures time is larger than the rated transmission power, but the maximum transmission. The above-mentioned output control signal for controlling so as to obtain a predetermined suppression transmission power smaller than the power is input from the transmission output limiter 9 to the power amplifier 3.

In the above embodiment, the timer circuit 12
When the switch 14 is turned off during the time counting, the transmission output power limiter 9 restarts the transmission signal power limiting operation.
The timer circuit 12 may be configured so that the transmission signal power limiting operation is continued even if the switch 14 is turned off during the predetermined time period.

In the above embodiments, the FM modulator 2 and the FM demodulator 7 are used. For example, PM, FSK, P
Modulators and demodulators of other modulation methods such as SK may be used.

[0030]

As described above in detail, according to the radio transmitter of the present invention, the transmission means for transmitting the transmission signal by radio, and the power of the transmission signal based on the transmission signal wirelessly transmitted from the transmission means. Is provided with a limiting means for limiting the value to a predetermined value and a controlling means for stopping or suppressing the operation of the limiting means for a required time. Therefore, the operation of the limiting means is temporarily stopped, whereby the transmission is performed. The means is in the predetermined maximum transmission output state for the predetermined time and can temporarily extend the communicable distance. Further, for example, when the power supply for supplying power to the transmitting means is a battery, the time in the maximum transmission output state is limited by the control means, so that the battery is supplied to the transmitting means and consumed. The amount of electric power can be limited, which allows the wireless transmitter to be used for a longer period of time as compared with the case where the control unit does not limit the amount of electric power.

[Brief description of drawings]

FIG. 1 is a block diagram of a wireless communication device that is an embodiment according to the present invention.

FIG. 2 is a block diagram of a conventional wireless communication device.

[Explanation of symbols]

 2 ... FM modulator, 3 ... Power amplifier, 9 ... Transmission output limiter, 10a ... Transmission / reception changeover switch, 11 ... DC power supply, 12 ... Timer circuit, 13, 14 ... Switch.

Claims (4)

[Claims] 1. A transmitting means for wirelessly transmitting a transmitting signal, a limiting means for limiting the power of the transmitting signal to a predetermined value based on the transmitting signal wirelessly transmitted from the transmitting means, and the limiting means for a required time. And a control means for stopping or suppressing the operation of the wireless transmitter. 2. The wireless transmitter further comprises a transmission instructing means for instructing to operate the transmitting means, and the control means has a predetermined period from when the operation of the transmitting means is instructed by the transmission instructing means. Timing means for timing the time, and operation control means for stopping or suppressing the operation of the limiting means from the time when the operation of the transmitting means is instructed by the transmission instructing means until the time is counted by the time measuring means for a predetermined time. The wireless transmitter according to claim 1, further comprising: 3. The wireless transmitter further includes a transmission instructing means for instructing to operate the transmitting means, and an operation of the control means when the operation of the transmitting means is instructed by the transmission instructing means. Selection means for selecting whether or not to start the operation, the control means includes time measuring means for measuring a predetermined time from when the operation of the control means is selected by the selection means, and the selection means. An operation control means for stopping or suppressing the operation of the limiting means from the time when the operation of the control means is selected to be started by the time measuring means until the time is measured for a predetermined time. The wireless transmitter according to claim 1. 4. The wireless transmitter further comprises stop instruction means for instructing to stop the operation of the operation control means during operation, and the control means is further operated by the stop instruction means. 4. The wireless transmitter according to claim 2, further comprising stop means for stopping the operation of the operation control means when an instruction to stop the operation is given during operation.