JPH1117582A - Portable radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent power supply voltage fluctuation in a PLL circuit in the portable radio equipment. SOLUTION: The radio equipment is provided with a secondary battery 22 being a power supply exclusive to a PLL circuit 8 in addition to a main battery 21 being a main power supply, a switch 26 that connects/disconnects the main battery 21 and the secondary battery 22, and the time applying a voltage from the main battery 21 to a radio signal amplifier demodulation section 2 or a transmission amplifier section 16 and the time to connect the switch 26 are controlled so as not to overlap with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable wireless device, and more particularly to a portable wireless device for preventing a power supply voltage of a PLL circuit from changing.

[0002]

2. Description of the Related Art A phase locked loop circuit (hereinafter referred to as a PLL circuit) I which operates at a low voltage due to the progress of semiconductor devices.
C and voltage controlled oscillators (hereinafter referred to as VCOs) have been developed one after another, and have been adopted for individually selected paging receivers and portable radios which can be provided with a transmission unit in the individually selected paging receiver and transmit a simple reply message. .

By the way, PLL circuits and VCOs are stable,
In addition, a frequency signal having a good signal-to-noise ratio (hereinafter referred to as C / N) must be supplied to the radio signal amplification / demodulation unit or the transmission amplification unit. If not, there is a possibility that the reception sensitivity may be degraded or the transmission frequency may fluctuate.

[0004]

However, a conventional portable wireless device is configured, for example, as shown in FIG.
At the time of reception and transmission, since a large current supply is required from the main battery 21 as the main power supply, the battery voltage may drop. The voltage of the main battery 21 is supplied to the PLL circuit 8 via a voltage stabilizer (hereinafter referred to as STB 23). However, when the battery voltage falls below the set voltage of the STB 23, the supply voltage to the PLL circuit 8 is no longer increased. If the supply voltage is not constant and the supply voltage is lower than the operation voltage of the PLL circuit 8, the PLL circuit 8 does not operate stably and cannot supply a stable and good C / N local oscillation signal frequency.

An object of the present invention is to provide a portable radio device capable of supplying a stable frequency signal with good C / N to a radio signal amplification / demodulation unit or a transmission amplification unit while keeping a supply voltage to a PLL circuit constant. Is to do.

[0006]

In order to solve the above problems, the present invention provides a local oscillation signal output from a voltage controlled oscillator, or a signal obtained by dividing the frequency of the local oscillation signal and a comparison result obtained by comparing the phase of a reference signal with a reference signal. A phase-locked loop circuit that sets a control voltage of the voltage-controlled oscillator, a radio signal amplification / demodulation unit that converts a received radio signal into an intermediate frequency band using the local oscillation signal and demodulates the signal, and a control voltage of the voltage-controlled oscillator. In a portable wireless device that includes a transmission amplifier that performs modulation amplification transmission by controlling the transmission signal voltage, and a main battery for power supply, and performs an intermittent reception operation and an intermittent transmission operation, the phase locked loop separate from the main battery A secondary battery for a power source of a circuit, and a first switch for connecting and disconnecting the main battery and the secondary battery, wherein the main battery is connected to the wireless signal amplification / demodulation unit or the transmission amplification unit. And controlling so that the time and connecting time between the first switch pressure supply do not overlap.

With such a configuration, the PLL
The supply voltage to the circuit is supplied by the secondary battery, and even if the voltage of the main battery drops, the switch separates the secondary battery from the main battery, so that a constant voltage is supplied to the PLL circuit,
It can operate stably.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a portable wireless device according to the present invention. In FIG. 1, when the SW 27 is turned on in accordance with an instruction from the control unit 20, the wireless signal amplification / demodulation unit (hereinafter referred to as a reception unit) 2 supplied with a voltage from the main battery 21
Works. The received signal input from the ANT 1 is amplified by the high-frequency amplifier 3 and passed through the bandpass filter 4.
Only the frequency signal desired to be received is selectively converted into an intermediate frequency by the mixer 5 by the local oscillation signal from the PLL circuit 8, extracted by the bandpass filter 6, and output to the intermediate frequency amplifier 7.
And demodulated by a demodulation unit (not shown).

The VCO 9 constitutes a part of the PLL circuit 8, and a signal from the VCO 9 is supplied to the prescaler 10
The frequency division signal is supplied to the variable frequency dividing circuit 11 and is divided by the predetermined frequency dividing ratio N. The frequency divided signal is supplied to the phase comparing circuit 12. Is done.

Further, an oscillation signal of the fixed oscillation circuit 14 is supplied to a frequency dividing circuit 15 to generate a frequency-divided signal of a reference frequency, and this signal is supplied to a comparing circuit 12, and the comparison output is supplied to a low-pass signal. The control voltage is supplied to the VCO 9 through the filter 13. Therefore, by controlling the frequency division ratio N, the VCO output signal changes in a predetermined frequency step, so that a desired frequency can be arbitrarily set in the frequency step.

The secondary battery 22 supplies a voltage to the STB 23 via the SW 25 controlled by the control unit 20,
The voltage stabilized by 23 is supplied to the PLL circuit 8. The STB 23 outputs a desired constant voltage when an input voltage higher than the output voltage is supplied, but cannot output a constant desired voltage when the input voltage falls below the output voltage, and outputs a voltage lower than the desired voltage with ripple. It has characteristics to output.

The secondary battery 22 is connected to the main battery 21 via the SW 26 controlled by the control unit 20 as shown in FIG. 1, and the secondary battery 22 is charged by the main battery 21 when the SW 26 is turned on and off. It is done or not done.

When the SW 28 is turned on in response to an instruction from the control unit 20, the booster circuit 24 boosts the voltage of the main battery 21,
The signal is supplied to the transmission unit 16 and is transmitted to a transmission amplification unit (hereinafter, referred to as a transmission unit).
16 operates. The transmission signal 29 is modulated by the VCO 9, and the modulated signal is further amplified by the high frequency amplifier 18 via the bandpass filter 17 and transmitted from the ANT 19.

Next, the operation of the embodiment of the present invention will be described. In order to receive the intermittently received signal, it is sufficient to intermittently set the receiving unit operating state (SW27 on) as shown in FIG. When the transmission signal is intermittently transmitted (SW 28 is turned on) as shown in FIG.
0 turns on SW25 before turning on SW27 and SW28 to operate the PLL circuit 8, and turns on SW27 and SW2.
SW25 is turned off simultaneously with turning off of 8.

At this time, the control unit 20 sets SW26 to SW2
The switch operation of the reverse logic is performed at the same timing as in step 5. That is, the control unit 20 turns off the switch SW26 before turning on the switches SW27 and SW28,
2 is stopped, SW26 is turned on at the same time as SW27 and SW28 are turned off, and charging is resumed.

In this way, the main battery 21 supplies a large current to operate the receiving unit 2 or the transmitting unit 16, and the receiving unit 2 or the transmitting unit 16 is operated even if the battery voltage drops. During operation, the voltage of the secondary battery 22 is completely disconnected from the main battery 21 because the SW 26 is always turned off, so that the voltage supplied to the STB 23 is not affected by any voltage drop. It is constant and does not decline.

Therefore, the oscillation frequency of the PLL is stable, and the C / N does not deteriorate.

[0019]

As described above in detail, in the portable radio of the present invention, even if the main battery supplies a large current and the voltage drops, the power supply voltage of the PLL circuit is constant without lowering. There is no fluctuation of the transmission frequency and no deterioration of the C / N, and therefore, it is possible to suppress the deterioration of the reception sensitivity and the fluctuation of the transmission frequency.

[Brief description of the drawings]

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

FIG. 2 is a time chart showing on / off operations of each switch of the embodiment shown in FIG. 1;

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1,19 ANT 2 Receiver (radio signal amplification / demodulation unit) 3,18 High frequency amplifier 4,6,17 Band filter 5 Mixer 7 Intermediate frequency amplifier 8 PLL circuit 9 VCO 10 Prescaler 11 Variable frequency divider 12 Phase comparator 13 Low-pass filter 14 fixed oscillator 15 frequency divider 16 transmission unit (transmission amplification unit) 20 control unit 21 main battery 22 secondary battery 23 STB 24 booster circuit 25 to 28 switch

Claims (4)

[Claims] A phase-locked loop circuit that uses a local oscillation signal output by a voltage-controlled oscillator or a signal obtained by dividing the frequency of the local oscillation signal and a reference signal as a control voltage of the voltage-controlled oscillator; A radio signal amplification and demodulation unit that performs frequency conversion of a received radio signal to an intermediate frequency band and demodulates the received radio signal using the local oscillation signal, and a transmission amplification unit that modulates and transmits the modulated voltage by controlling the control voltage of the voltage controlled oscillator with the transmission signal voltage A portable wireless device including a main battery for power supply and performing intermittent reception operation and intermittent transmission operation; a secondary battery for power supply of the phase-locked loop circuit separate from the main battery; A first switch for connecting / disconnecting to / from a next battery; and a time for the main battery to supply a voltage to the wireless signal amplification / demodulation unit or the transmission amplification unit and a time for connecting the first switch. Portable radio and controls so as not to overlap. 2. The secondary battery is charged by the main battery by closing the first switch at a time other than the time when the main battery supplies a voltage to the wireless signal amplification / demodulation unit or the transmission amplification unit. The portable wireless device according to claim 1, wherein A second switch provided between said secondary battery and said phase locked loop circuit, wherein said main battery supplies a voltage to said radio signal amplifying / demodulating unit or transmission amplifying unit according to said second switch. 3. The portable wireless device according to claim 1, wherein the switch is closed and the secondary battery supplies a voltage to the phase locked loop circuit. 4. When the main battery does not supply a voltage to the radio signal amplification / demodulation unit or the transmission amplification unit, the second switch is opened to prevent the secondary battery from supplying a voltage to the phase locked loop circuit. 4. The system according to claim 3, wherein the operation is stopped.
The described portable radio.