JP2000082779A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver which can be reduced in size and stabilized in operation and can be manufactured by a simplified manufacturing process. SOLUTION: A broadcast radio receiver 100 is for receiving an FM broadcast. It is constituted of a semiconductor chip 10 for receiving, a quartz oscillator 40, a stereophonic demodulation circuit 50, an audio adjusting section 60, a power amplifier 70, a speaker 80, and an antenna 90. The semiconductor chip 10 for receiving is constituted of a CMOS integrated circuit which is an integrated high frequency analog circuit 20, a frequency synthesizer 30, a stereophonic demodulation circuit 50, and an audio adjusting section 60, all of which are formed on a single semiconductor substrate. The high frequency analog circuit 20, etc., are formed into a single chip and thereby are handled as one component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for receiving various signals using a frequency synthesizer.

[0002]

2. Description of the Related Art In radio broadcasting, a broadcasting station sends
A signal obtained by modulating an audio signal using a modulation method such as modulation or FM modulation is transmitted. For this reason, the radio receiver demodulates the received signal according to the modulation method, and performs audio output from the speaker by performing volume adjustment and the like.

FIG. 5 is a diagram showing a configuration of a conventional radio receiver. A radio receiver 500 shown in FIG. 1 is a radio receiver using a superheterodyne system, and is a high-frequency analog circuit 5 that performs a predetermined reception process on a broadcast signal.
10 and a frequency synthesizer 52 for outputting a local oscillation signal mixed with the broadcast signal and controlling its frequency.
0, a crystal oscillator 530 connected to the frequency synthesizer 520, and a stereo demodulation circuit 540 for demodulating an L signal (left audio signal) and an R signal (right audio signal) from a composite signal output from the high frequency analog circuit 510. , An audio adjustment unit 550 that adjusts the volume and sound quality of the L signal and the R signal, a power amplifier 560 that amplifies and outputs the L signal and the R signal according to the volume adjustment by the audio adjustment unit 550, and performs audio output. It is configured to include a speaker 570 and an antenna 580 for receiving a broadcast signal. The user can listen to a desired broadcast by instructing the radio receiver 500 to select a channel or adjust the volume.

[0004]

The high-frequency analog circuit 510 constituting the radio receiver 500 described above.
The frequency synthesizer 520 and the like are manufactured and sold as separate functional components, and the radio receiver 500 is assembled by combining these components.

[0005] However, since the high-frequency analog circuit 510 and the like are separate functional parts, the area required for assembling these parts increases. In particular, portable radio receivers are required to be as small as possible, but an increase in the area required for assembly has hindered miniaturization. Also, the signal line connecting the high-frequency analog circuit 510 and the frequency synthesizer 520 is long,
If they are arranged close to other signal lines, noise will be mixed into the signal lines, and the high-frequency analog circuit 510
Sometimes became unstable. In addition, the manufacturer of the radio receiver 500 and the like,
Since the frequency synthesizer 520 and the frequency synthesizer 520 are respectively assembled, there is a problem that the manufacturing process is complicated and the number of steps is increased.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to provide a receiver capable of miniaturizing and stabilizing the operation and simplifying the manufacturing process.

[0007]

In order to solve the above-mentioned problems, in a receiver according to the present invention, a high-frequency analog circuit that performs a predetermined receiving operation involving a frequency conversion process on an input signal and outputs an audio signal. , An audio adjustment unit for performing an adjustment process on an audio signal, and a frequency synthesizer for outputting an oscillation signal used for the frequency conversion process and controlling the frequency thereof are integrally formed on a single semiconductor substrate, thereby forming a CMOS integrated circuit. Is composed. By integrally forming the frequency synthesizer and the high frequency analog circuit to the audio adjustment unit on the semiconductor substrate, the area required for assembling the components is reduced.
The receiver can be reduced in size. Further, a signal line connecting the high-frequency analog circuit and the frequency synthesizer is shortened, and noise mixed in this signal line can be suppressed, and the operation of the high-frequency analog circuit can be stabilized. further,
Since the components from the high-frequency analog circuit to the audio adjustment unit and the frequency synthesizer can be assembled as a single component, the number of components at the time of assembly is reduced, and the manufacturing process can be simplified.

Further, by configuring a CMOS integrated circuit in which a high-frequency analog circuit and the like are integrally formed, power consumption can be reduced. Furthermore, since an analog switch can be formed by a CMOS integrated circuit, adjustment of an audio signal (for example, adjustment of volume and sound quality)
Can be easily performed.

Particularly, when a guard ring for noise reflection is formed between the high-frequency analog circuit and the frequency synthesizer, the noise generated from the frequency synthesizer is suppressed from being mixed into the high-frequency analog circuit. The operation of the circuit can be further stabilized.
Further, the high-frequency analog circuit and the frequency synthesizer may be arranged apart from each other by a predetermined distance. Also in this case, it is possible to suppress noise generated from the frequency synthesizer from being mixed into the high-frequency analog circuit, and to further stabilize the operation of the high-frequency analog circuit.

[0010] A shield member may be provided to prevent external noise from entering, and a frequency synthesizer from the high-frequency analog circuit to the audio adjustment section may be arranged inside the shield member. Since the shield member prevents external noise from being mixed in, the operation of the high-frequency analog circuit can be further stabilized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a radio receiver according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of the radio receiver.
The radio receiver 100 shown in FIG. 1 is for receiving an FM broadcast, and includes a receiving semiconductor chip 10, a quartz oscillator 40, a power amplifier 70, a speaker 80, and an antenna 9
0 is included.

The receiving semiconductor chip 10 is a CMOS integrated circuit in which a high-frequency analog circuit 20, a frequency synthesizer 30, a stereo demodulation circuit 50, and an audio adjustment unit 60 are formed on a single semiconductor substrate such as silicon. That is, the high-frequency analog circuit 20, the frequency synthesizer 3
0, the stereo demodulation circuit 50 and the audio adjustment unit 60 are 1
Chipped and treated as a single component. Therefore, the high-frequency analog circuit 20 and the like can be assembled as a single component,
The area required for assembling is reduced. Further, a signal line connecting the high-frequency analog circuit 20 and the frequency synthesizer 30 is shortened, and noise mixed in the signal line can be suppressed.

The receiving semiconductor chip 10 is a CMO.
Since it is an S integrated circuit, power consumption can be reduced. Further, the output characteristics of the MOS field effect transistor used in the CMOS integrated circuit pass through the origin (when the voltage of the gate terminal is 0, no current flows between the drain terminal and the source terminal). Since the symmetry in both the positive and negative directions is good, the audio adjustment unit 60 as an analog switch can be formed by the CMOS integrated circuit, and the volume and sound quality can be easily adjusted.

The high frequency analog circuit 20 receives a predetermined FM broadcast signal and performs demodulation processing and the like, and includes a high frequency receiving circuit 21, a frequency conversion circuit 22, an intermediate frequency amplification circuit 23, and a detection circuit 24. Have been.

The high-frequency receiving circuit 21 includes an antenna tuning circuit and a high-frequency amplifier circuit, performs high-frequency amplification on the FM broadcast signal input from the antenna 90, and outputs the amplified FM broadcast signal.

The high frequency receiving circuit 2
By mixing the amplified FM broadcast signal output from 1 with the local oscillation signal output from the frequency synthesizer 30, an intermediate frequency signal obtained by converting the frequency of the FM broadcast signal is output. For example, when a desired FM broadcast signal to be received is input to the frequency conversion circuit 22, the signal is mixed with a local oscillation signal output from the frequency synthesizer 30 to convert the signal into an intermediate frequency signal of 10.7 MHz. .

The intermediate frequency amplifier 23 amplifies the intermediate frequency signal output from the frequency converter 22 and
A tuning operation for extracting only a signal near 0.7 MHz is performed. The detection circuit 24 performs FM detection on the amplified intermediate frequency signal output from the intermediate frequency amplification circuit 23 and outputs a composite signal. As a specific FM detection method, for example, there is a method in which a change in frequency of an intermediate frequency signal is temporarily converted into a change in amplitude, and AM detection is performed on the converted signal.

The frequency synthesizer 30 is for controlling and outputting the frequency of a local oscillation signal, and includes a voltage controlled oscillator (VCO) 31 for outputting a local oscillation signal,
A frequency divider 32 having a frequency division ratio N for dividing the local oscillation signal output from the CO 31, a reference oscillator 33 for outputting a reference frequency signal determined by the crystal oscillator 40, a divided local oscillation signal and a reference frequency The phase comparator 34 includes a phase comparator 34 for comparing a phase with a signal, and a low-pass filter (LPF) 35 for outputting a DC voltage for controlling the VCO 31 in accordance with a result of the phase comparison by the phase comparator 34.

The operation of the frequency synthesizer 30 is as follows. For example, when the VCO 31 needs to output a local oscillation signal having a frequency of N × fr,
When 31 outputs a local oscillation signal of frequency fosc, frequency divider 32 divides this local oscillation signal into a signal of frequency fosc / N and outputs the signal to phase comparator 34. On the other hand, the reference oscillator 33 outputs a reference frequency signal having a frequency fr determined by the crystal unit 40 to the phase comparator 34. The phase comparator 34 outputs the frequency fosc / N output from the frequency divider 32.
Is compared with the signal of the frequency fr output from the reference oscillation 33 to determine the phase difference, and output a signal having a duty ratio according to the comparison result. The LPF 35 feeds back a DC control voltage corresponding to the signal output from the phase comparator 34 to the VCO 31. The VCO 31 controls fosc / N and f
The oscillation frequency is changed so that r becomes equal, that is, fosc becomes equal to N × fr, and the frequency N × fr
Output the local oscillation signal.

The stereo demodulation circuit 50 demodulates the L signal and the R signal from the composite signal output from the detection circuit 24. The audio adjustment unit 60 includes the stereo demodulation circuit 5
The volume and sound quality of the L signal and the R signal output from 0 are adjusted. Specifically, the audio adjustment unit 60 adjusts the volume of the L signal and the R signal by changing the gain of the power amplifier 70 at the subsequent stage. The audio adjustment unit 60 includes a built-in variable resistor for sound quality adjustment (not shown).
Is changed stepwise by switching the analog switch in multiple stages, and the sound quality is adjusted for the L signal and the R signal. The power amplifier 70 amplifies the L signal and the R signal according to the gain adjusted by the audio adjustment unit 60. These amplified L and R signals are output as audio from the speaker 80.

As described above, the radio receiver 1 of the present embodiment
Reference numeral 00 denotes the receiving semiconductor chip 1 which is a CMOS integrated circuit by the high-frequency analog circuit 20, the frequency synthesizer 30, the stereo demodulation circuit 50, and the audio adjustment unit 60.
0 is configured. That is, the high-frequency analog circuit 2
0, frequency synthesizer 30, stereo demodulation circuit 50,
The audio adjustment unit 60 is made into one chip. By integrating the high-frequency analog circuit 20 and the like into one chip, the area required for assembling the components is reduced as compared with the conventional case where the high-frequency analog circuit 20 and the like are separate functional components. 100 can be reduced in size. In addition, by forming a single chip, the signal line connecting the high-frequency analog circuit 20 and the frequency synthesizer 30 is shortened, and noise mixed in this signal line is suppressed, and the operation of the high-frequency analog circuit 20 is stabilized. it can. Further, since the high-frequency analog circuit 20 and the like can be assembled as a single component, the number of components at the time of assembly is reduced, and the manufacturing process can be simplified.

The receiving semiconductor chip 10 is a CMO.
Since it is an S integrated circuit, power consumption can be reduced. Further, since the audio adjustment unit 60 as an analog switch can be formed by the CMOS integrated circuit, it is possible to easily adjust the volume and the sound quality.

In the above-described embodiment, the positional relationship between the high-frequency analog circuit 20 and the frequency synthesizer 30 constituting the semiconductor chip 10 for reception is not particularly taken into consideration, but, for example, the reception shown in FIG. Semiconductor chip 11-1 and the receiving semiconductor chip 1 shown in FIG.
1-2, a guard ring 1 for noise reflection is provided between the high-frequency analog circuit 20 and the frequency synthesizer 30.
2 may be formed. By forming the guard ring 12, noise generated from the frequency synthesizer 30 is prevented from being mixed into the high-frequency analog circuit 20,
The operation of the high-frequency analog circuit 20 can be further stabilized.

The receiving semiconductor chip 13 shown in FIG.
As described above, the high-frequency analog circuit 20 and the frequency synthesizer 30 may be arranged at a predetermined distance from each other. By arranging them at a predetermined distance, noise generated from the frequency synthesizer 30 is prevented from entering the high-frequency analog circuit 20, and the operation of the high-frequency analog circuit 20 can be further stabilized.

The receiving semiconductor chip 14 shown in FIG.
As described above, a shield member 15 such as a resin mold for preventing external noise from being mixed may be provided, and the high-frequency analog circuit 20 and the like may be disposed inside the shield member 15. Since the noise from the outside is prevented by the shield member 15, the operation of the high-frequency analog circuit 20 can be further stabilized.

In the above-described embodiment, the LPF 35 is incorporated in the receiving semiconductor chip 10. However, when the area occupied by the capacitor included in the LPF 35 increases (when a large time constant is required), the LPF 35 is used. May be connected to the outside of the semiconductor chip 10 for reception.

In the above embodiment, a radio receiver for receiving FM broadcasts has been described as an example. However, a radio receiver for receiving other broadcasts other than FM broadcasts, such as AM broadcasts and PCM broadcasts, and FM broadcasts are described. The present invention can also be applied to a receiver for receiving other media such as a radio receiver and a television receiver capable of receiving both AM broadcasts and a receiver for receiving signals other than broadcast signals. . In these cases, a receiving semiconductor chip may be constituted by a frequency synthesizer and at least a high-frequency analog circuit for receiving each broadcast signal to an audio adjustment unit.

[0028]

As described above, according to the present invention, the area required for assembling components can be reduced by integrally forming the frequency synthesizer and the high frequency analog circuit to the audio adjustment unit on a single semiconductor substrate. Because of the reduction, the receiver can be downsized. Also, the signal line connecting the high-frequency analog circuit and the frequency synthesizer becomes shorter,
The operation of the high-frequency analog circuit can be stabilized by suppressing the noise mixed into the signal line. Furthermore, since the high-frequency analog circuit and the frequency synthesizer can be assembled as a single component, the number of components at the time of assembly is reduced, and the manufacturing process can be simplified.

Further, by forming a CMOS integrated circuit by integrally forming a high-frequency analog circuit and the like, power consumption can be reduced. Further, since an analog switch can be formed by a CMOS integrated circuit, adjustment of an audio signal can be easily performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a radio receiver according to an embodiment.

FIG. 2 is a diagram showing a receiving semiconductor chip on which a guard ring is arranged.

FIG. 3 is a diagram showing a receiving semiconductor chip in which a high-frequency analog circuit and a frequency synthesizer are formed separately.

FIG. 4 is a diagram illustrating a receiving semiconductor chip in which a high-frequency analog circuit, a frequency synthesizer, a stereo demodulation circuit, and an audio adjustment unit are arranged inside a shield member.

FIG. 5 is a diagram showing an overall configuration of a conventional radio receiver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Receiving semiconductor chip 20 High frequency analog circuit 30 Frequency synthesizer 31 Voltage controlled oscillator (VCO) 40 Crystal oscillator 50 Stereo demodulation circuit 60 Audio adjustment unit 70 Power amplifier 80 Speaker 90 Antenna 100 Radio receiver

Claims (4)

[Claims] 1. A high-frequency analog circuit that performs a predetermined receiving operation involving a frequency conversion process on an input signal to output an audio signal, an audio adjustment unit that adjusts the audio signal, and an audio adjustment unit that is used for the frequency conversion process. And a frequency synthesizer for outputting an oscillating signal and controlling the frequency of the oscillating signal, and wherein the frequency synthesizer from the high-frequency analog circuit to the audio adjustment unit and the frequency synthesizer are integrally formed on a single semiconductor substrate. A receiver comprising: 2. The receiver according to claim 1, wherein a guard ring is formed on the semiconductor substrate, between the high-frequency analog circuit and the frequency synthesizer. 3. The receiver according to claim 1, wherein the high-frequency analog circuit and the frequency synthesizer are arranged at a predetermined distance on the semiconductor substrate. 4. The high-frequency analog circuit according to claim 1, further comprising a shield member on the semiconductor substrate for preventing external noise from being mixed therein. A receiver comprising an audio adjustment unit and the frequency synthesizer.