JPH06164445A - Wide-band voltage control oscillation circuit - Google Patents

Abstract

PURPOSE:To provide a wide-band voltage controlled oscillation circuit which can cover a wide frequency range just with a single VCO and therefore can reduce the entire size and the cost of the oscillation circuit. CONSTITUTION:The output signal S1 of a voltage controlled oscillation means 1 is multiplied by a multiplying means 2 so that a high frequency signal S2 is transmitted. A signal S3 is passed through a variable frequency BPF 3 whose frequency pass band is set by the 1st control voltage V1 so as to transmit a high frequency signal of a prescribed frequency level. Then the signal S3 is amplified by a 1st amplifier 4 which is turned on by the 2nd control voltage V2 and then transmitted as a transmitting local oscillation signal S4. Furthermore the signal S3 that passed through the BPF 3 whose frequency pass band is set so as to transmit the high frequency signal of another frequency level is amplified by a 2nd amplifier 5 that is turned on by 3rd control voltage V3 and then transmitted as a receiving local oscillation signal S5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide band voltage controlled oscillator circuit. 2. Description of the Related Art In recent years, the number of subscriber terminals (mobile terminals) in mobile communication has been rapidly increasing, and the demand for digital mobile terminals is increasing in particular.

This digital mobile terminal requires two voltage controlled oscillators (VCOs) for obtaining a local oscillation signal (local oscillation signal) for transmission / reception, which increases cost and size. I'm becoming.

Therefore, there is a demand for a wideband voltage controlled oscillator circuit which can reduce the cost and downsize the digital mobile terminal.

[0004]

2. Description of the Related Art In an analog mobile terminal, a channel is set by frequency-dividing a signal output from one VCO to obtain a local oscillator signal having a different frequency.

Further, in the digital mobile terminal,
Channel setting is performed by time division, and two VCOs that output signals of different frequencies are used in order to obtain local oscillation signals of different frequencies during transmission and reception.

[0006]

However, in the above-mentioned digital mobile terminal, since the two VCOs are used, there is a problem that the size of the entire terminal becomes large and the cost becomes high.

The present invention has been made in view of the above circumstances, and a wide frequency range can be supplemented by a single VCO, thereby achieving downsizing of the entire circuit and cost reduction. It is an object of the present invention to provide a wideband voltage controlled oscillator circuit capable of achieving the above.

[0008]

FIG. 1 shows the principle of the present invention. In the figure, 1 is a voltage-controlled oscillation means. Reference numeral 2 denotes a multiplication means, which multiplies the frequency f of the output signal S1 of the voltage controlled oscillation means 1 and outputs a harmonic signal S2.

Reference numeral 3 denotes a variable frequency band pass filter, which has a frequency pass band arbitrarily set by the first control voltage V1 and passes a harmonic signal S2 having the same frequency band as the set frequency pass band. .

Reference numeral 4 denotes a first amplifying means, which is turned on / off by a second control voltage V2, amplifies the signal S3 which has passed through the variable frequency band pass filter 3 when it is turned on, and outputs it as a local signal for transmission S4. To do.

Reference numeral 5 denotes a second amplifying means, which is turned on / off by a third control voltage V3, amplifies the signal S3 which has passed through the variable frequency bandpass filter 3 when it is turned on, and outputs it as a local signal for reception S5. To do.

[0012]

In the present invention described above, for example, the frequency 3f, which is three times the frequency f of the output signal S1 of the voltage controlled oscillation means 1, passes through the frequency pass band of the variable frequency band pass filter 3 by the first control voltage V1. Thus, at this time, the first amplifying means 4 is turned on and the second amplifying means 5 is turned off by the first and second control voltages V2 and V3.

In this case, the output signal S1 of the voltage controlled oscillating means 1 is multiplied by the multiplying means 2 so that the harmonic signal S2 is output to the bandpass filter 3 and the harmonic of the frequency 3f of the harmonic signal S2 is outputted. The wave signal S2 passes through the band pass filter 3, and the passed signal S3 is amplified by the first amplifying means 4 and output as the local signal for transmission S4.

On the other hand, the frequency pass band of the band pass filter 3 is 4f, which is four times the frequency f of the output signal S1 of the voltage controlled oscillator 1 by the first control voltage V1.
Is set to pass through, and at this time, the first amplifying means 4 is turned off and the second amplifying means 5 is turned on by the first and second control voltages V2 and V3.

In this case, the harmonic signal S2 output from the multiplying means 2 is output to the variable frequency bandpass filter 3, and the harmonic signal S2 of the frequency 4f of the harmonic signal S2 is output.
Passes through the band pass filter 3 and the passed signal S
3 is amplified by the second amplifying means 5, and the local signal for reception S is received.
It is output as 5.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the configuration of a wideband voltage controlled oscillator circuit according to an embodiment of the present invention.

The wideband voltage controlled oscillator circuit shown in this figure is
The VCO 1, the multiplier 2, the variable frequency bandpass filter (variable frequency BPF) 3, and the amplifiers 4 and 5 are provided.

The VCO 1 outputs the signal S1 having the frequency f ₀ . The multiplier 2 outputs the output signal S1 of VCO1.
Outputs a high-frequency signal S2 multiplied by 2f, 3f, 4f, ..., And an amplifier 11 having an input end connected to an output end of the VCO 1, and an output end of the amplifier 11. Self-biasing resistor 1 connected between grounds
2 and a step recovery diode 13 are provided.

The multiplying action is due to the diode 13, and from the change of the capacitance with respect to the reverse voltage, the diode 1
This is caused by a rapid change in the capacitance that occurs when the high frequency voltage applied to 3 overdrives from the reverse direction to the forward direction.

In the variable frequency BPF 3, the coil 14, the capacitor 14 and the varactor diode 15 connected in series with each other are connected in parallel between the output terminal of the multiplier 2 and the ground, and the coil 17 is connected between the capacitor 14 and the varactor diode 15. The control voltage V1 is supplied via the.

By changing the control voltage V1 to change the capacitance of the varactor diode 16 and controlling the resonance frequency of the LC resonator by the coil 14 and the capacitor 15, the pass band of the filter is set. .

That is, assuming that the pass band is set to pass the signal of the frequency 3f, the high frequency signal S2 of the frequency 3f output from the multiplier 2 passes. The passed signal is designated as S3.

The amplifiers 4 and 5 have a control voltage V
The on / off of the power source is controlled by transistor switches (switches) 18 and 19 which are turned on / off according to V2 and V3.

The amplifier 4 amplifies the signal S3 that has passed through the variable frequency BPF3 and outputs it as a local transmission signal for transmission (local transmission signal for transmission) S4.
The signal S3 that has passed through F3 is amplified and output as a local signal for reception (local signal for reception) S5.

However, the frequency f of the output signal S1 of the VCO 1
Is lower than the frequencies of the transmission local signal S4 and the reception local signal S5. In such a configuration,
It is assumed that the frequency f of the output signal S1 of the VCO 1 is 100 MHz.

If a local oscillation signal S4 of 300 MHz is used for transmission and a local oscillation signal S5 of 400 MHz is used for reception,
The pass band of the BPF 3 is set so that the high-frequency signal S2 of 300 MHz passes by the control voltage V1 at the time of transmission, and the pass band of the BPF 3 is set at 400 by the control voltage V2 at the time of reception.
The pass band of the BPF 3 may be set so that the high frequency signal S2 of MHz passes.

The switch 18 is turned on by the control voltage V2 at the time of transmission, the switch 19 is turned off by the control voltage V3, and the switch 18 is turned off by the control voltage V2 at the time of reception, and the control voltage V
It may be controlled so that the switch 19 is turned on by 3.

According to the wideband voltage controlled oscillator circuit described above, a wideband transmission local oscillator signal S4 and a wideband reception local oscillator signal S5 can be obtained by one VCO1. Therefore,
The entire circuit can be made smaller and the cost can be made lower than in the past.

[0029]

As described above, according to the wideband voltage controlled oscillator circuit of the present invention, one VC can be used in a wide frequency range.
There is an effect that it can be supplemented with O, and there is an effect that it is possible to reduce the size and cost of the entire circuit.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a diagram showing a configuration of a wideband voltage controlled oscillator circuit according to a first embodiment of the present invention.

[Explanation of symbols]

 1 Voltage Control Oscillation Means 2 Multiplier Means 3 Variable Frequency Bandpass Filter 4 First Amplifier 5 Second Amplifier V1 First Control Voltage V2 Second Control Voltage V3 Third Control Voltage

Claims (1)

[Claims] 1. A wide-band voltage-controlled oscillation circuit for outputting a transmission local oscillation signal and a reception local oscillation signal in different frequency bands used during transmission and reception of a wireless communication device, comprising: voltage control oscillation means (1); The frequency pass band is arbitrary by the multiplication means (2) that multiplies the frequency (f) of the output signal (S1) of the controlled oscillation means (1) and outputs the harmonic signal (S2), and the first control voltage (V1). The harmonic signal in the frequency band set by this setting
Variable frequency bandpass filter that passes (S2) (3)
Then, the power is turned on / off by the second control voltage (V2), and when turned on, the signal (S3) that has passed through the variable frequency bandpass filter (3) is amplified and output as the local signal for transmission (S4). The power supply is turned on / off by the first amplifying means (4) and the third control voltage (V3), and when turned on, the signal (S3) that has passed through the variable frequency bandpass filter (3) is amplified and transmitted to the receiving station. And a second amplifying means (5) for outputting as a signal (S5).