JPH0471369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmission output switching device in a wireless transmitting/receiving device.

Configuration of conventional example and its problems FIG. 1 shows a conventional transmission output multi-stage switching device. The configuration of this conventional example will be explained below with reference to FIG. 1. Figure 1 is a functional block diagram, where 1 is the front section of the transmitter, 2 is the power amplification section (PA
3 is a power amplifier section (hereinafter referred to as PA section), 4 is a directional coupler (hereinafter referred to as a directional coupler), 5 is an antenna switching means, and 7 is a low-pass filter (hereinafter referred to as a directional coupler).
(referred to as LPF) 8 is the antenna terminal, 9 is the receiver,
10 is a voltage comparator (hereinafter referred to as a comparator) 11 is a power controller, 18 is a transmission switch (hereinafter referred to as a PT switch) 19 is a constant voltage circuit, 20 is a power supply voltage terminal, 21 is a reference voltage source for the comparator 10, S ₁ , _S2 , _S3
is an output switch that sets the transmission output, and HS is a hand switch for press talk.

Next, the operation of the above conventional example will be explained. The front section 1 excites the excitation section 2 with an output of a transmission frequency f _T of several + mW, and the excitation section 2 outputs an output of about 0.1 W to vibrate the PA section 3. , the antenna terminal 8 via the antenna switch 5 and the LPF 7.
A predetermined output at frequency f _T is output to the antenna.

On the other hand, the traveling wave output of the transmission is detected from connection 4,
In addition to the comparator 10, it is compared with a first reference voltage E _s of a reference voltage source 21, and is negatively fed back to the excitation unit 2 via the power controller 11. As a result, the reference voltage source 21
Comparator 1 compares _the reference voltage E _s of
When E _s > E _d , the power controller 11 increases the voltage and supplies large power, and when E _s < E _d , lowers the voltage and supplies small power, so that E _s ≒ E It is controlled so that _d .

However, in the conventional method of controlling the excitation section 2 or the power amplifier 3 to vary the output, when the output is low, the output from the connection 4 decreases, resulting in an increase in error, and the power amplifier 3 has an input of 0. However, they often require a certain amount of DC power consumption, which makes it difficult to switch the output over a wide range, such as lower efficiency at low output.

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the above-mentioned conventional examples, and aims to provide a transmission output switching device capable of wide power switching with a relatively simple configuration.

Configuration of the Invention In order to achieve the above object, the device of the present invention has the following features:
If the output decreases to, for example, one-tenth of the PA section output, the operation of the PA section is stopped and a switch is installed at the PA section input to output the excitation section output to the antenna via a separate route. This aims to reduce battery power consumption.

DESCRIPTION OF EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the circuit configuration of the present invention.
8, 9, 10, 11, 18, 19, and 20 represent the same names as the same numbers in FIG. 6 is an excitation output route switch (means), 6, 1 is an input switching unit (means) for the PA section, 6, 2 is a route switch unit (means), R ₁ and R ₂ are resistors for the first reference voltage R ₃ is the resistor for the second reference voltage, S ₁ and S ₂ are the first, second, and third transmission outputs (the first output is the maximum and the third output is the minimum). Output switch to determine,
HS is a hand switch used for press talk communication.

Next, the operation of the above embodiment will be explained using FIGS. 2 and 3. First, in Fig. 2, the front section 1 of the transmitter uses a crystal oscillator, a multiplier section, or a frequency synthesizer in the case of multiple frequencies to set the transmission frequency f _T at a level of several mW to several tens of mW to the excitation section 2.
Output to. The excitation section 2 outputs about 100 to 200 mW. The input switching units 6,1 are configured to switch the output to the PA unit 3 side for the first and second outputs, and to the route switching units 6,2 for the third output.
The PA section 3 amplifies the output of the excitation section 2 and connects it to the output section 4.
The signal is outputted to the antenna terminal 8 via the antenna switch 5 and LPF 7, and a prescribed transmission power is radiated from the antenna connected thereto.

On the other hand, the detection voltage E _d of the traveling wave component of the connection 4 is output from the connection 4 to the voltage comparator 10, and is connected to the resistor R ₁ ,
The first reference voltage E _s set by R ₂ , that is, the first reference voltage determined by resistors 106 and 107 in FIG.
It is compared with E _s and is negatively fed back from the power controller 11 to the excitation unit 2, and operates so that E _d ≈E _s . Second
In the case of output, the resistors R ₁ , R ₂ , R ₃ are set to the second reference voltage _EL by the switch S ₂ , and E _{d ≈EL} .
In the case of the third output, the power supply to the PA section 3 is reduced or stopped, and the outputs of the input switching sections 6 and 1 are switched to the route switching sections 6 and 2, and are sent to the antenna via the antenna switching device 5 and LPF 7. Terminal (ANT)
8. At this time, the reference voltage of the comparator 10 is the first reference voltage _Es , and the detection output from the connection 4 is almost 0, so the output of the excitation section 2 is the maximum value (0.1 to 0.2 W), and the antenna It is output to terminal 8.

Figure 3 is a specific circuit diagram of the block diagram in Figure 2. When the press talk hand switch HS is not pressed and is OFF, power is supplied to the receiver 9, and the power supply to the transmitter section is cut off. It is becoming. Next, when the hand switch HS for press talk is turned on, the base of the switch transistor 181 of the PT switch 18 is connected to the resistor 182 and the diode 183.
becomes the ground potential, switches the output voltage V _cc of the constant voltage circuit 19, supplies it as a voltage V _dd to the front stage section 1 as a load, the excitation section 2, the comparator 10, the power controller 11 and the route switch 6. Power is supplied to one end of the relay 51 of the antenna switch 5. When the transmission output is the first output, the relay 51
The other end is a diode 53, a transistor 161,
Switch _S1 sets it to earth potential, and relay 51
is turned ON, and the antenna switch 55 is set to the receiving side contact a.
Switch from contact b to transmitting side contact b. On the other hand, the base of the switch transistor 131 of the PA section controller 13 is grounded through the resistor 132, transistor 161, and _S1 , and supplies power to the amplifier in the front stage section 1, as well as to the resistor 63, diode 61, and switch coil 62. supply and turn on diode 61
Then, the output of the excitation section 2 is applied to the PA section 3, and the output of the excitation section 2 is applied to the PA section 3.
The output is connection 4, antenna switch 55, LPF 7,
It is output to the antenna via the antenna terminal 8.
A part of the traveling wave of the connection 4 is outputted to the comparator 10 by the load resistor 42 and the coupling capacitor 43, which outputs the detection voltage E _d of the detector circuit's resistor 44, diode 45, capacitor 46, and variable resistor 47 to the comparator 10. Voltage E _s
Negative feedback control is performed so that E _s ≒ E _d . For the second output, the voltage dividing resistor 107 is adjusted by adjusting the resistor 14, the diode 151, the diode 171,
The second reference voltage E _L is set by switch _S2 , and the base of transistor 131 of PA controller 13 is grounded by resistor 132, diode 152, transistor 171, and output switch _S2.
Power is supplied to the PA section 3 to operate it. Third
To obtain the transmission output of , the output switches S ₁ and S ₂ should be
OFF, both the ground side circuits of the relay 51 of the antenna switching device 5 are OFF, so the relay 51 is inoperative and the antenna switching switch 55 is OFF.
is connected to receiving side a. Also, the PA control unit 131 is OFF, so the diode 61 is OFF,
V _dd forms a circuit through the resistor 112 and R ₁ , the diode 64 , and the choke coil 62 , and with the diode 64 in a conductive state, the output of the excitation section is applied to the diode 67 through the diode 64 and the bypass capacitor 65 . Diode 67 is V _dd , resistor 1
12, R ₂ , the diode 67, the λ/4 (λ: wavelength) stripline 68 and the diode 69 become conductive, and the contact a of the antenna switch 55
The signal is output to the antenna via the LPF 72 and the antenna terminal 8. The input to the receiver 9 forms a λ/4 stopper circuit with the λ/4 stripline and the diode 69, which lowers the input to the receiver and makes the contact with the diode 67 high impedance. The excitation output is not affected by the branch circuit to the receiver and can output all the power to the antenna side. Note that the switch circuit 12 is in the first output state and the second output state.
This circuit is in an ON state and makes the diode 64 non-conductive.

Figure 4 shows the operation of the transmission output switches S ₁ and S ₂ , the transmission output P _O , and the comparison voltage E _c of the comparator (depending on the output
E _s and E _L correspond) and antenna switch 55
shows the switching direction.

Note that although the circuit including the output switches S ₁ and S ₂ is shown as mechanical contacts, the circuit including output switches S 1 and S 2 is shown as a controller (not shown).
This may be done using a microcomputer using the signal.

Further, in the above description, the antenna switching device and the contacts are configured using relays, but it goes without saying that semiconductor switches or the like may be used for these.

Effects of the Invention As explained above, the present invention has a configuration in which the output of the excitation section is input to the power amplification section and the output is obtained as the transmission output via the antenna switcher. When using power, the output of the excitation section is configured to be guided to the antenna switching device via a route switching device configured using a diode or the like via a separate route without passing through the power amplification section. Since the circuit is provided with a circuit that operates as a stopper and is configured to share the path from the receiver's antenna switch to the receiver, it has the advantage of being able to have a wide power variable range with a simple configuration. Moreover, since the reduced output route is configured to be completely separated from the normal power path by a contact point, it is not affected by the output capacity of the PA section, and there is no power loss during reduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional transmission output device, FIG. 2 is a configuration block diagram of a transmission output switching device in an embodiment of the present invention, and FIG. 3 is a specific circuit with the configuration of FIG. 2. FIG. 4 is an explanatory diagram showing the relationship between the output switch position and the comparison voltage in FIG. 3, and the relationship with the antenna switching device contact point. 2...Excitation section, 3...Power amplifier, 4...Connection, 5...Antenna switcher, 6, 1...Input switcher, 6, 2...Route switcher, 8...Antenna terminal, 9 ... Receiver, 10 ... Comparator, 18 ... Press talk switch, S ₁ , S ₂ ... Output switch,
a, b...a of the antenna switch 5 is the receiving side contact,
b is the contact on the sending side.

Claims (1)

[Claims] 1. Input switching means for switching and selecting the output of the excitation section during transmission between a normal output via a power amplifier and another route for obtaining a reduced output, and a transmitting side contact connected to the output of the power amplifier, and at the time of reception. and a receiving side contact used at the time of reduced transmission output, and selectively connecting either the transmitting side contact or the receiving side contact to the antenna terminal by operating a press talk switch; Route switching means is provided between the contact and the input switching means and includes a diode biased so as to pass the transmission frequency and stop the reception frequency; and a stopper circuit that stops the receiving frequency and passes the received frequency, and when transmitting the normal output, the output of the excitation section is amplified by the power amplification section and output to the antenna terminal via the transmission side contact of the antenna switching means, so that the frequency is reduced. When transmitting an output, the transmitting output switching device outputs the output of the excitation unit to the antenna terminal via the receiving side contact of the input switching means, the route switching means, and the antenna switching means, and stops the operation of the power amplifier.