JPH0846428A - Digitally controlled oscillator circuit - Google Patents

Abstract

PURPOSE:To provide a digitally controlled oscillator circuit for sharing control parts in a portable telephone set and compensating the temperature of a crystal oscillator. CONSTITUTION:In this digitally controlled oscillator circuit 22 of a portable telephone set for switch a CPU 1, a memory 20, a temperature sensor 23, a D/A converter 21 and an A/D converter 24 are used as the control parts, control information for correcting the deviation of the temperature and the output frequency of the portable telephone set is stored in the memory 20 beforehand, the temperature of the oscillator circuit 22 is detected by the temperature sensor 23 and a signal converted in the A/D converter 24 is inputted to the CPU 1. The CPU 1 outputs a correction signal corresponding to the control information. stored in the memory 20, the correction signal is converted into an analog value in the D/A converter 21 and inputted to the oscillator circuit 22 as a control voltage and the output frequency of the portable telephone set is constantly controlled to a prescribed frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digitally controlled oscillator circuit for a mobile phone, and in particular, by sharing the parts used for temperature compensation with the parts used in the main body of the mobile phone, a significant cost reduction can be achieved. The present invention relates to a digitally controlled oscillator circuit.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a block configuration example of a conventional digital temperature-compensated crystal oscillator. As shown in the figure, the conventional digital temperature-compensated crystal oscillator 60 includes an oscillation circuit 61 using a crystal oscillator, a temperature sensor 62, and an A / D converter 6.
3, CPU (central processing unit) 64, D / A converter 65,
It is composed of an integrating circuit 66 and a memory circuit 67.

The crystal oscillator has a temperature characteristic that the oscillation frequency changes with temperature changes.
(For details, see FIG. 3) holds a constant output frequency by correcting with a control voltage corresponding to a temperature change. In advance, the storage circuit 67 stores control information (voltage value) for correcting the deviation of the resonance frequency due to the temperature change. The temperature sensor 62 detects the temperature of the oscillation circuit 61 and detects the temperature of the A / D converter 63.
Is converted into a digital value and output to the CPU 64. CPU
Reference numeral 64 refers to the correction information stored in the storage circuit 67 and outputs a control signal (digital signal) corresponding to the temperature D /
The D / A converter 65 outputs the analog value to the A converter 65, outputs the analog value to the oscillation circuit 61 via the integration circuit 66, and holds the output frequency at a predetermined constant frequency.

FIG. 3 is a diagram showing a configuration example of the oscillation circuit 61 of FIG. The oscillation frequency of the oscillation circuit 61 is the crystal unit 4
5, the capacitances of the capacitors 43, 44, 46 and 47 and the variable capacitance diode 42. The frequency signal oscillated by the crystal oscillator 45 is amplified by the transistor 50 and output from the output terminal through the capacitor 56. The resonance frequency of the crystal unit 45 changes due to temperature changes (± 10 pp
The variable capacitance diode 42 is an element having a temperature characteristic of approximately m) and the capacitance of which varies according to an applied voltage.
Therefore, when the temperature of the crystal unit 45 changes, the CPU
64 (FIG. 2) can control the voltage of the input terminal of the oscillation circuit 61 by the above-described method to control the output frequency output from the output terminal to a constant value.

[0005]

However, the conventional digital temperature-compensated crystal oscillator shown in FIG. 2 is complicated and large in size. Further, when a defect occurs because the temperature is corrected according to the temperature characteristics of the crystal unit 45, only the crystal unit 45 cannot be replaced and the entire unit is replaced, which is expensive. Further, there is a problem that the target of temperature compensation is the frequency at the output end of the oscillation circuit 61, and the output frequency output from the antenna is not the target of temperature compensation.

The present invention has been made in view of the above points, and in order to eliminate the above-mentioned problems, a digital control type oscillation circuit for sharing temperature control of a crystal oscillator by sharing control parts used in a mobile phone. The purpose is to provide.

[0007]

In order to solve the above problems, the present invention provides a digital signal for a mobile phone using a CPU, a memory, a temperature sensor, a D / A converter, and an A / D converter as control components. In the control type oscillation circuit, control information for correcting the shift of the output frequency of the mobile phone due to temperature change is stored in advance in the memory, and the temperature of the digital control type oscillation circuit is detected by the temperature sensor 23 as shown in FIG. Then
The signal converted by the A / D converter 24 is input to the CPU 1,
The CPU 1 outputs a correction signal according to the control information stored in the memory 20, converts it into an analog value by the D / A converter 21 and inputs it as a control voltage to the digital control type oscillation circuit, and outputs the output frequency of the mobile phone to a predetermined value. Is controlled to a constant frequency.

[0008]

In the present invention, the crystal oscillator 45 and the variable capacitance diode 4 are used without using the conventional digital temperature compensation crystal oscillator.
The temperature sensor 62, the A / D converter 63, the CPU 64, and the D / A shown in FIG.
Since the converter 65, the integrating circuit 66, and the memory circuit 67 are commonly used in the mobile phone in the past, they are miniaturized,
The parts can be shared and the price can be reduced. In addition, since the output frequency of the antenna 9 is targeted, more accurate control than in the past can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a block configuration example of a mobile phone using the digital control type oscillation circuit of the present invention. As shown in the figure, a mobile phone using the digital control type oscillation circuit of the present invention includes a CPU (central processing unit) 1, a data signal processing device 2, a base band unit 3 for transmitting and receiving, and a modulator 4. , A mixer 5 for frequency conversion, an amplifier 6, an output adjusting unit 7, an antenna duplexer 8, an antenna 9,
Amplifier 10, mixer 11, amplifier 12, mixer 13, demodulator 14, PLL (phase locked loop) 15, VCO
(Voltage controlled oscillator) 16, PLL 17, VCO 18, automatic output adjuster 19, memory 20 for storing data, D /
A converter 21, oscillation circuit 22, temperature sensor 23, A / D
Converter 24, display device 30, key pad 31 for transmitting dial signals, etc., interface 32 for connecting to the outside,
It is composed of a transmitter 33 and a receiver 34. The oscillation circuit 22 has the configuration example shown in FIG.

The dial signal transmitted from the key pad 31 is processed by the CPU 1 and displayed on the display device 30.
The signal processed by the CPU 1 is sent to the data signal processing unit 2 and the base.
The signal is processed as a transmission signal by the band unit 3, modulated by the modulator 4, frequency-converted by the mixer 5, amplified by the amplifier 6, and transmitted through the output adjusting unit 7, the antenna duplexer 8 and the antenna 9. The transmitted signal is similarly processed and transmitted from the transmitter 33 through the base band unit 3.

The received signal from the other party is received by the antenna 9, amplified by the amplifier 10 through the antenna duplexer 8, frequency-converted by the mixer 11, amplified by the amplifier 12, further frequency-converted by the mixer 13, and demodulated by the demodulator 14. It is processed as a received signal in the base band unit 3 and is output as a voice in the handset 34.

The oscillator circuit 22 outputs a constant frequency and supplies it to the modulator 4 and the PLL 15, and the output of the PLL 15 is VC.
The output frequency of O16 is controlled and mixed by the mixer 5 to convert the output signal into a predetermined transmission frequency. CPU1 uses PLL1 to oscillate a predetermined frequency according to the channel used.
Control 5 The frequency of the received signal is also converted by the mixer 11 at the output frequency of the VCO 16.

On the other hand, the oscillating circuit 22 is a PLL 17 for reception.
Also outputs a constant frequency to the output signal of the VCO 18 and controls the output frequency of the VCO 18 to convert the received signal into a predetermined frequency by the mixer 13. The CPU 1 controls the output frequency of the VCO 18 by adjusting the PLL 17 so as to convert it into a predetermined frequency according to the reception channel frequency.

Next, the temperature correction control of the oscillator circuit 22 will be described. In advance, correction data (control voltage value) for correcting deviation of the output frequency of the antenna 9 due to temperature change is stored in the memory 20.
Is stored. The temperature sensor 23 detects the temperature of the oscillation circuit 22, converts it into a digital value by the A / D converter 24, and outputs it to the CPU 1. The CPU 1 refers to the correction data stored in the memory 20 and outputs a control voltage value (digital signal) corresponding to the corresponding temperature to the D / A converter 21, and the D / A converter 21 outputs an analog signal. The output frequency of the antenna 9 is maintained at a predetermined constant frequency by converting the value into a value and outputting the value to the oscillation circuit 22 to control the frequency.

Conventionally, a mobile phone has been used under severe environmental conditions, and a temperature sensor 23 has been used in order to adapt to temperature changes. The D / A converter 21 is also used as an analog converter for the input signal of the automatic output adjuster 19 and the audio digital signal. The A / D converter 24 is also used as a digital audio converter. Of course, the CPU 1 and the memory 20 are also used for control. The one used as the temperature compensation of the oscillation circuit 22 is used in common, and by arranging the oscillator circuit 22 in the vicinity of the temperature sensor 23, downsizing and cost reduction are achieved.

[0016]

As described in detail above, according to the present invention, the following excellent effects are expected. (1) Temperature sensor used for temperature compensation, A / D converter,
Since the CPU, the D / A converter, and the memory circuit are commonly used in the mobile phone, it is possible to achieve downsizing, sharing of parts, and cost reduction.

(2) Further, since the control target is the output frequency output from the antenna of the mobile phone, the control can be performed more accurately than before.

(3) Further, only the oscillation circuit can be replaced.

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration example of a mobile phone using a digital control type oscillation circuit of the present invention.

FIG. 2 is a diagram showing a block configuration example of a conventional digital temperature-compensated crystal oscillator.

FIG. 3 is a diagram showing an example of the oscillation circuit of FIGS. 1 and 2.

[Explanation of symbols]

 1 CPU (Central Processing Unit) 2 Data Signal Processing Device 3 Base Band Unit 4 Modulator 5 Mixer 6 Amplifier 7 Output Adjusting Unit 8 Antenna Duplexer 9 Antenna 10 Amplifier 11 Mixer 12 Amplifier 13 Mixer 14 Demodulator 15 PLL ( Phase locked loop) 16 VCO (voltage controlled oscillator) 17 PLL (phase locked loop) 18 VCO (voltage controlled oscillator) 19 Automatic output regulator 20 Memory 21 D / A converter 22 Oscillation circuit 23 Temperature sensor 24 A / D converter 30 display device 31 keypad 32 interface 33 transmitter 34 receiver

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoji Suwa 2-14-9 Tamagawadai, Setagaya-ku, Tokyo Kyocera Corporation Tokyo Yoga Works (72) Inventor Juichi Hiramoto 2-14 Tamagawadai, Setagaya-ku, Tokyo 9 Kyocera Corporation Tokyo Yoga Office

Claims (1)

[Claims] 1. A digital control type oscillation circuit of a mobile phone using a CPU, a memory, a temperature sensor, a D / A converter, and an A / D converter as control components, wherein the temperature of the memory is changed in advance. Control information for correcting the output frequency shift of the mobile phone is stored, the temperature of the digital control type oscillation circuit is detected by the temperature sensor, and the signal converted by the A / D converter is output by the CPU.
The CPU outputs a correction signal in accordance with the control information stored in the memory, converts it into an analog value by the D / A converter, and inputs it as a control voltage to the digital control type oscillation circuit, and outputs the correction signal. A digitally controlled oscillator circuit characterized by controlling the output frequency of a telephone to a predetermined constant frequency.