JP2001168753A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver having excellent convenience which enables a user to check the reception by a receiver single body without using a measurement device or an opposite station or providing a measurement part in the receiver in adjustment. SOLUTION: In checking, a noise squelch circuit connected to a demodulator detects the presence/absence of radiated radio waves from demodulation output signals, a microcomputer controls a clock signal frequency so as to make the frequency of the radiated radio waves be in a reception frequency band and judges whether or not the output of the noise squelch circuit is in the reception frequency band and thus, the reception operation is checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver having a reception check function.

[0002]

2. Description of the Related Art FIG.
This will be described with reference to FIG. The details of this receiver are shown in Japanese Patent Application No. 11-191684. FIG.
Is a block diagram showing a configuration of a conventional receiver, FIG. 3 is a circuit diagram showing an example of a configuration of a clock oscillator of the conventional receiver, and FIG. 4 is a circuit diagram showing an example of a configuration of a clock oscillator of the conventional receiver. is there.

[0003] The operation of a conventional receiver will be described. First, an outline of the operation of the receiver will be described with reference to FIG. The high-frequency signal received by the antenna 1 is band-limited and amplified by the front end 2 and transmitted to the first mixer 3. In the first mixer 3, the frequency of the high-frequency signal is converted to a first intermediate frequency. (The frequency conversion to the first intermediate frequency will be described in detail later.) After the frequency conversion, the high-frequency signal is band-limited by the bandpass filter 4, amplified by the first intermediate-frequency amplifier 5, and sent to the second mixer 6. Transmitted. In the second mixer 6, the frequency of the high-frequency signal is further converted to a second intermediate frequency. This frequency conversion is performed by mixing the high-frequency signal transmitted from the first intermediate frequency amplifier 5 and the oscillation signal transmitted from the second local oscillator 12. After the frequency conversion, the high-frequency signal is band-limited by the band-pass filter 7, amplified by the second intermediate frequency amplifier 8, and an audio signal is extracted from the high-frequency signal by the demodulator 9. This audio signal is subjected to band limiting processing by the baseband signal processing circuit 10 and output from the speaker 11.

Next, frequency conversion of a high-frequency signal (frequency conversion to a first intermediate frequency) will be described with reference to FIG. This frequency conversion is performed by mixing a high-frequency signal transmitted from the front end 2 and an oscillation signal transmitted from the first local oscillator 13. The oscillation frequency of the oscillation signal is set to a predetermined frequency by the microcomputer 14. The microcomputer 14 operates according to the clock signal output from the clock oscillator 15.

Next, the operation of the clock oscillator 15 will be described with reference to FIGS. First, the operation of the clock oscillator shown in FIG. 3 will be described in detail. The clock signal frequency is determined by the crystal oscillator 16, the capacitors 17, 18
Is determined by The processing speed of the microcomputer 14 and the baseband circuit 10 is determined by the clock signal frequency, and the clock signal at this frequency becomes the source of MSK signal processing, CTCSS, and CDCSS processing of the baseband circuit 10. A radio wave having a frequency that is a multiple of the clock signal frequency is radiated from a pattern or an element on the substrate of the microcomputer 14 or the baseband processing circuit 10. When the frequency of this radio wave is within the bandwidth of the reception frequency, a problem may occur that the reception sensitivity is deteriorated. Next, the operation of the clock oscillator shown in FIG. 4 will be described in detail. FIG.
Is configured such that when the frequency of the radiated radio wave is within the bandwidth of the reception frequency, the microcomputer 14 controls the frequency of the radio wave to be outside the band of the reception frequency. The clock oscillator 15 includes a crystal oscillator 16, capacitors 17 to 20, a variable capacitance diode 2
1, 22, resistors 23 and 24, and control signal lines 26 and 27 from the microcomputer 14. The clock signal frequency is determined by the oscillation frequency of the crystal unit 16 and the electric capacitance of the capacitors 17 to 20 and the variable capacitance diodes 21 and 22. The electric capacitance of the variable capacitance diodes 21 and 22 changes according to the level of a control signal from the microcomputer 14. Normally, the control signal from the microcomputer 14 is at L level, but changes to H level when the clock signal frequency is changed.
When a clock signal is transmitted from the clock oscillator 15,
Since the microcomputer 14 and the baseband processing circuit 10 perform processing such as waveform shaping and frequency division, radio waves having a frequency multiplied by the clock signal frequency are generated from a pattern or element on the substrate of the microcomputer 14 or the baseband processing circuit 10. Is radiated. The microcomputer 14 determines whether or not the frequency of the radiated radio wave is within the reception band. When it is determined that the frequency is within the reception band, the control signal is changed to the H level to change the clock signal frequency so that the frequency of the radiated radio wave is outside the reception band.

As described above, in the conventional receiver, the reception sensitivity is degraded by controlling the clock signal frequency so that the frequency of the radiated radio wave which is a multiple of the clock signal frequency is out of the range of the reception bandwidth of the reception frequency. To prevent

[0007]

The above-mentioned conventional receiver can prevent the deterioration of the receiving sensitivity. However, in order to check the receiving operation, it is necessary to use a measuring instrument or a partner station for talking, or to use it alone. When checking the receiving operation, it is necessary to newly provide a measuring unit. Therefore, when the inspection is performed by using the measuring instrument, the inspection is performed by using the partner station of the call, and the inspection is performed by itself, there are the following disadvantages.

[0008] Since the expenditure of a measuring instrument or the like is imposed on a general user, it becomes expensive. Before using the receiver in normal operation, or when checking the reception operation at a predetermined time, it is necessary to check the reception operation using one or more transmitters, which are partner stations, which is troublesome. Since it is necessary to newly provide a measuring unit, it is disadvantageous for miniaturization and weight reduction and is expensive. For example, when the reliability of communication (whether or not reliable reception is possible) affects human life, such as in a disaster prevention wireless system, it is necessary to check the receiver before communication. When this receiver is portable, the provision of a new measuring unit is incompatible with miniaturization and weight reduction.

In view of the above-mentioned drawbacks, the present invention makes it possible to inspect the reception operation by itself without using a measuring instrument and a counterpart station or newly providing a measuring unit at the time of inspection. An object is to provide a convenient receiver.

[0010]

In order to achieve the above object, the present invention comprises detection means connected to demodulation means for detecting the presence or absence of a radiated radio wave from a demodulated output signal at the time of inspection. The clock signal frequency is controlled so that the frequency of the radiated radio wave is within the reception frequency band, and the output of the detection unit is determined to be within the reception frequency band. Then, when the radiated radio wave is controlled to be within the reception frequency band by controlling the clock signal frequency, it is determined whether or not the receiving operation can be performed depending on whether or not the radiated radio wave can be received.

Alternatively, an operating means connected to the receiving section for setting the receiving frequency so that the frequency of the radiated radio wave is within the receiving frequency band, and presence / absence of the radiated radio wave from the demodulated output signal at the time of inspection connected to the demodulating means. And control means for determining whether the output of the detection means is within the reception frequency band. Then, when the reception frequency is adjusted so that the radiated radio wave falls within the reception frequency band, it is determined whether or not the reception operation can be performed depending on whether or not the radiated radio wave can be received.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A receiver according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the receiver of this embodiment. FIG. 4 is a circuit diagram showing the configuration of the clock oscillator of the receiver according to the present embodiment.

First, an outline of the operation of the receiver will be described with reference to FIG. The high frequency signal received by the antenna 1 is band-limited or amplified by the front end 2 and transmitted to the first mixer 3. In the first mixer 3, the frequency of the high-frequency signal is converted to a first intermediate frequency. (The frequency conversion to the first intermediate frequency will be described in detail later.) After the frequency conversion, the high-frequency signal is band-limited by the bandpass filter 4, amplified by the first intermediate-frequency amplifier 5, and sent to the second mixer 6. Transmitted. In the second mixer 6, the frequency of the high-frequency signal is further converted to a second intermediate frequency. This frequency conversion is performed by mixing the high-frequency signal transmitted from the first intermediate frequency amplifier 5 and the oscillation signal transmitted from the second local oscillator 12. After the frequency conversion, the high-frequency signal is band-limited by the band-pass filter 7, amplified by the second intermediate frequency amplifier 8, and demodulated by the demodulator 9.
Then, an audio signal is extracted from the high-frequency signal. When a normal receiving operation is performed, the audio signal is subjected to band limiting processing in the baseband signal processing circuit 10 and output from the speaker 11. At this time, the clock frequency output from the clock oscillator 15 is controlled so that the high-frequency signal received from the antenna does not include noise (noise generated by radiated radio waves) from the microcomputer 14 (which is the control means of the present embodiment). I do. (The operations of the microcomputer 14 and the clock oscillator 15 will be described later in detail.) On the other hand, when checking the receiving operation, the high-frequency signal received from the antenna includes noise from the microcomputer 14 (noise generated by radiated radio waves). Clock oscillator 15 to include
Controls the clock frequency output from. (Microcomputer 1
4. The operation of the clock oscillator 15 will be described later in detail. Then, the noise squelch circuit 25 (which is the detecting means of the present embodiment) detects whether or not noise generated by the radiated radio wave is included, and the microcomputer 14 determines. When the noise generated by the radiated radio wave is detected by the noise squelch circuit 25, the microcomputer 14 determines that the receiving operation can be performed.

Next, frequency conversion of a high-frequency signal (frequency conversion to a first intermediate frequency) will be described with reference to FIG. This frequency conversion is performed by mixing a high-frequency signal transmitted from the front end 2 and an oscillation signal transmitted from the first local oscillator 13. The oscillation frequency of the oscillation signal is set to a predetermined frequency by the microcomputer 14. The microcomputer 14 operates according to the clock signal output from the clock oscillator 15.

Next, the operation of the clock oscillator 15 will be described with reference to FIG. The clock oscillation frequency of the clock oscillator 15 shown in FIG. When a normal reception operation is performed, control is performed so that the frequency of the radiated radio wave is out of the reception frequency band.
On the other hand, when checking the reception operation, control is performed so that the frequency of the radiated radio wave falls within the band of the reception frequency. The clock oscillator 15 includes a crystal oscillator 16, a capacitor 17 to
20, variable capacitance diodes 21, 22, resistors 23, 2
4. Control signal lines 26 and 27 from the microcomputer 14 are provided. The clock signal frequency is the oscillation frequency of the crystal oscillator 16, the capacitors 17 to 20, the variable capacitance diode 21,
22. Since the electric capacitance of the variable capacitance diodes 21 and 22 changes according to the level of the control signal from the microcomputer 14, radiation is performed by changing the level of the control signal according to whether the reception operation is performed or the reception operation is checked. The frequency of the received radio wave can be switched outside or within the band of the reception frequency.

For example, the reception frequency fR = 154.825
0 (MHz) and reception bandwidth B = 12 (KHz),
When performing the reception operation, the clock signal frequency fC = 3.68 so that the frequency of the radiated radio wave is out of the band of the reception frequency.
Set to 66 (KHz). (All the multiplied waves of the clock signal are out of the band of the reception frequency.) On the other hand, when checking the reception operation, the clock signal frequency fC = 3.686 so that the frequency of the radiated radio wave is within the band of the reception frequency.
Set to 4 (KHz). (The 42nd harmonic of this clock signal falls within the band of the reception frequency.) Even when the reception frequency fR ≠ 154.8250 (MHz), the frequency of the radiated radio wave is out of the band of the reception frequency when performing the reception operation. Obviously, when confirming the receiving operation, the frequency of the radiated radio wave can be set within the band of the receiving frequency. Therefore, even in the case of a multi-channel receiver, the frequency of the radiated radio wave is switched out of the receiving frequency band or in the band by changing the level of the control signal depending on whether the receiving operation is performed or the receiving operation is checked. Obviously you can.

As described above, the receiver according to the present embodiment can independently check the receiving operation. Inspection of the reception operation can be performed according to the operation of the operator by connecting a changeover switch to the microcomputer 14, for example.
Further, the microcomputer 14 can be operated so that the receiving operation can be checked when the power of the receiver is turned on, for example. Then, as a result of checking the receiving operation, when the operation is normal, the operation shifts to the normal receiving operation. When the operation is abnormal, the operator can be notified by, for example, an alarm display or an alarm sound.

In this embodiment, the case where the noise squelch circuit is used as the detecting means has been described, but the present invention is not limited to this. If the detection means detects that the radio wave is radiated from the control means, the reception operation can be checked by itself. In the case of a multi-channel receiver, instead of controlling the clock signal frequency as in the present embodiment, the reception frequency is adjusted by operating a channel switch so that the radiated radio waves fall within the reception frequency band. The receiving operation can be checked.

[0019]

As described above, according to the present invention, the frequency of the radiated radio wave is adjusted to be within the reception frequency band, and it is determined whether to receive the radiated radio wave.
Inspection of the receiving operation can be performed independently without using a measuring instrument or a partner station or newly providing a measuring unit in the receiver. Therefore, an extremely convenient receiver can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a receiver according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a receiver as an example of the related art.

FIG. 3 is a circuit diagram showing a configuration of a clock oscillator of a receiver as an example of the related art.

FIG. 4 is a circuit diagram illustrating a configuration of a clock oscillator of a receiver according to an example of the related art and an example of the present invention.

[Explanation of symbols]

1: Antenna 2: Front end 3: First mixer 4: Band filter 5: First intermediate frequency amplifier 6: Second mixer 7: Band filter 8: Second intermediate frequency amplifier 9: Demodulator 10: Baseband signal Processing circuit 11: Speaker 12: Second local oscillator 13: First local oscillator 14: Microcomputer 15: Clock oscillator 16: Crystal oscillator 17: Capacitor 18: Capacitor 19: Capacitor 20: Capacitor 21: Variable capacitance diode 22: Variable capacitance Diode 23: resistor 24: resistor 25: noise squelch 26: control signal line 27: control signal line

Continued on the front page F term (reference) 5K020 DD02 DD03 DD05 EE05 FF00 GG11 KK04 MM04 MM11 MM12 NN01 NN10 5K042 CA02 CA12 DA03 DA13 EA03 FA12 FA29 JA01 NA03 NA04 5K052 AA03 BB04 DD16 EE12 EE17 FF26 GGA CC13 GG26 CC51 CC53 HH04 JJ05 JJ06 JJ09 JJ12

Claims (2)

[Claims] 1. A receiving unit for receiving a signal from a partner station, a frequency converting unit connected to the receiving unit for converting a frequency of a received signal into a required value, and a control unit for controlling an operation of the frequency converting unit. A clock oscillator for generating and outputting a clock signal for operating the control means, and a demodulation means provided at a subsequent stage of the frequency conversion means for converting to an audio signal. Detecting means for detecting the presence or absence of radiated radio waves from the demodulated output signal, wherein the control means controls the clock signal frequency so that the frequency of the radiated radio waves is within a receiving frequency band, and the output of the detecting means is a receiving frequency. Control means for judging whether a signal is within a band or not, wherein the receiver is configured to independently check a reception operation. 2. A receiving section for receiving a signal from a partner station, frequency converting means connected to the receiving section for converting the frequency of the received signal to a required value, and control means for controlling the operation of the frequency converting means. A clock oscillator that generates and outputs a clock signal for operating the control means, and a demodulation means provided at a subsequent stage of the frequency conversion means and converts the signal into an audio signal. Operating means for setting the receiving frequency so that the frequency is within the receiving frequency band, and detecting means connected to the demodulating means for detecting the presence or absence of radiated radio waves from the demodulated output signal at the time of inspection, the control means The receiver is a control unit that determines whether the output of the detection unit is within a reception frequency band, and is configured to independently check the reception operation.