JP2001016125A - Reception equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide reception equipment, which can perform self-diagnosis on the fault of a reception circuit, in simple configuration without providing any transmission circuit or transmission antenna for transmitting a signal for self-diagnosis. SOLUTION: An amplifier circuit 32 capable of outputting an RSSI signal (voltage signal) corresponding to a received signal level is used for an amplifier circuit in a detection/demodulation circuit 30 for receiving a reception signal from the reception circuit for processing the reception signal and on the side of a fault discriminating circuit 40, the RSSI signal provided by the level detecting function of this amplifier circuit 32 is compared with a reference voltage Vref2 as a fault discrimination value. When the RSSI signal is lower than the reference voltage Vref2, the fault of the reception circuit is discriminated. As a result, it is not necessary to provide the transmission circuit or transmission antenna for transmitting the signal for fault diagnosis in order to diagnose the fault of the reception circuit and the reception equipment having the fault diagnostic function can be inexpensively realized in simple configuration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus having a self-diagnosis function for diagnosing a failure in a receiving circuit.

[0002]

2. Description of the Related Art Conventionally, a receiving apparatus having a self-diagnosis function of this kind transmits a signal for self-diagnosis as disclosed in Japanese Patent Publication No. 2786122, for example. The receiver circuit receives the signal and compares the information obtained by the receiver circuit with the information used to generate the self-diagnosis signal, thereby diagnosing the failure of the receiver circuit. It is configured to be.

FIG. 4 shows an example of the configuration of a conventional device having a self-diagnosis function. As shown in FIG. The received signal is processed, a specific received signal is extracted, and the extracted received signal is detected and demodulated to obtain desired received data included in the received signal. A self-diagnosis transmission circuit 56 is provided which converts (modulates) the transmission data into a transmission signal and transmits the transmission signal from the transmission antenna 58. At the time of failure diagnosis of the receiving circuit 54, a transmission signal obtained by modulating a carrier with transmission data is transmitted via the transmission circuit 56 for self-diagnosis and the transmission antenna 58, and the transmission signal is transmitted to the receiving antenna 52 and the receiving circuit 52. A receiving circuit 54 receives and demodulates the received data via a transmission circuit 54 and compares the received data obtained as a result of the demodulation with the transmission data inputted to the transmission circuit 56 for self-diagnosis.
Are compared, it is determined whether or not each data matches, and when each data does not match, the failure of the receiving circuit 54 is determined.

However, in such a conventional failure diagnosis method, it is necessary to incorporate a transmission circuit 56 and a transmission antenna 58 for failure diagnosis in the receiving device, and the configuration of the device becomes complicated, and the receiving device cannot be downsized. There was a problem that it could not be realized at low cost. Also,
The self-diagnosis transmission circuit 56 is provided with an oscillation circuit for generating a carrier wave for data transmission. However, there is a problem that a failure of the reception circuit is erroneously determined due to a failure of the oscillation circuit or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a receiving apparatus capable of self-diagnosis of a failure of a receiving circuit without providing a transmitting circuit or a transmitting antenna for transmitting a signal for failure diagnosis. It is an object of the present invention to be able to realize the configuration at a low cost.

[0006]

According to a first aspect of the present invention, there is provided a receiving apparatus for detecting and demodulating a signal received from a receiving signal. A specific received signal is selected, and the detection / demodulation means detects and demodulates the selected received signal to extract an information signal included in the received signal. Further, the detection / demodulation means has a level detection function for detecting the signal level of the reception signal output from the signal selection means, and the self-diagnosis means detects the level of the reception signal obtained by the level detection function of the detection / demodulation means. By comparing the signal level with a preset failure determination value, when the signal level of the received signal is lower than the failure determination value, a failure in the receiving system from the receiving means to the detection / demodulation means is determined.

That is, the receiving apparatus of the present invention uses the level detection function of the detection / demodulation means instead of transmitting a signal for failure diagnosis for failure diagnosis of the receiving system as in the conventional apparatus. Then, based on the signal level of the received signal input to the detection / demodulation means, the failure of the receiving system is self-diagnosed.

Therefore, according to the receiving apparatus of the present invention, it is not necessary to provide a transmission circuit or a transmitting antenna for transmitting a signal for failure diagnosis, unlike the conventional apparatus, for diagnosing a failure in the receiving system. With such a configuration, it is possible to self-diagnose a failure in the receiving system. Here, as the level detection function of the detection / demodulation means, an RSSI function generally incorporated for a received signal strength indication (RSSI) in a conventional receiving apparatus may be used. Therefore, it is not necessary to provide a special circuit for detecting the reception signal level.

Further, the failure of the receiving system can be determined from the signal level of the received signal obtained by the level detecting function of the detecting / demodulating means because the receiving means and the signal processing means constituting the receiving system operate normally. In this case, even if there is no transmission signal from the external device, the signal processing means outputs noise in the same frequency band as the reception signal to be detected and demodulated, so that the signal level of the reception signal becomes zero. From detection and demodulation means, although at a low level,
This is because a detection signal corresponding to the signal level of the received signal is output.

Therefore, the failure judgment value used by the self-diagnosis means for performing the failure diagnosis of the receiving system includes the failure judgment value when the receiving means and the signal processing means are operating normally and no external transmission signal is received. On the basis of the signal level of the received signal obtained by the level detection function of the detection and demodulation means,
A value lower than this signal level may be set.

A plurality of values are set as failure judgment values, and the self-diagnosis means compares the signal level of the received signal with the plurality of failure judgment values. You may. With this configuration, the self-diagnosis unit can determine the failure of each part of the receiving system corresponding to each failure determination value.

For example, the receiving apparatus is a general receiving apparatus such as a radio receiving apparatus, and the signal processing means includes an amplifying circuit for amplifying a received signal, a local oscillation circuit for generating a reference frequency signal, and an amplifying circuit. A mixing circuit that mixes the amplified reception signal with the reference frequency signal from the local oscillation circuit and converts a specific reception signal to be detected and demodulated into a predetermined intermediate frequency signal. It is assumed that a specific received signal converted into an intermediate frequency signal by the mixing circuit is detected and demodulated. In this case, the signal level obtained when only the amplifier circuit is not operating in the signal processing unit, the signal level obtained when only the mixing circuit is not operating in the signal processing unit, and the entire signal processing unit is not operating If the obtained signal level and the like are obtained by experiments or simulations, and based on those values, a plurality of failure judgment values corresponding to the failure points of the signal processing means are set, the self-diagnosis means:
By comparing the plurality of failure determination values with the signal level obtained by the level detection function of the detection / demodulation means, it is possible to identify the location of a failure in the signal processing means, and the failure of the reception system Then, repairs such as replacement of parts can be performed promptly.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the entire receiving apparatus to which the present invention is applied. As shown in FIG.
The receiving apparatus of the present embodiment includes a receiving antenna 10 for receiving an externally transmitted radio wave as a receiving unit. And
An output (received signal) from the receiving antenna 10 is passed through a band-pass filter (BP) that passes a signal in a predetermined frequency band.
F) Input to a mixing circuit (mixer) 18 via an amplification circuit 14 for amplifying a reception signal passed through the BPF 12 and 12, and the mixer 18 mixes the signal with an oscillation signal of a predetermined frequency generated by the oscillation circuit 16. Is converted into a predetermined intermediate frequency signal.

The received signal frequency-converted to the intermediate frequency signal by the mixer 18 is converted into a band-pass filter (BP) that passes only a specific received signal converted to the intermediate frequency.
F) The signal is input to a detection / demodulation circuit 30 serving as a detection / demodulation unit via 20). The detection / demodulation circuit 30
Detects and demodulates a received signal input via the BPF 20 to restore data such as audio included in the received signal, and outputs the restored received data to a data processing circuit at a subsequent stage.

Further, in the receiving apparatus of the present embodiment, a receiving circuit (specifically, a BPF 12 and an amplifying circuit 14) as signal processing means provided on a signal path from the receiving antenna 10 to the detection / demodulation circuit 30 is provided. , An oscillator circuit 16, a mixer 18, and a BPF 20).

The failure determination circuit 40 is a circuit corresponding to the self-diagnosis means of the present invention. The failure determination circuit 40 receives a RSSI (Received Signal Strength Indication) signal output from the detection / demodulation circuit 30 separately from the received data. To determine the presence of a received signal and the presence / absence of a received signal, to notify the user of the failure in the receiving system, and to instruct the subsequent data processing circuit to start data processing.

Hereinafter, the configurations of the failure determination circuit 40 and the detection / demodulation circuit 30 will be described with reference to FIG. As shown in FIG. 2, the detection / demodulation circuit 30 includes an amplification circuit 32 for amplifying a reception signal input via the BPF 20 and a detection circuit 3 for detecting the reception signal amplified by the amplification circuit 32.
4 and a low-pass filter (LPF) for selectively passing a detection signal (detection signal) detected by the detection circuit 34
36, and a comparator 38 that compares a detection signal passed through the LPF 36 with a preset reference voltage Vref0 and converts the detection signal into a binary signal (reception data).

As shown in FIG. 3, the amplifying circuit 32 is connected to a well-known IC that generates an RSSI signal whose voltage value changes according to the signal level (reception level) of the reception signal input via the BPF 20. It is configured. Note that an IC having such a level detection function is conventionally known as an IC for amplifying a received signal or an IC for detection and demodulation including an amplifying circuit for a received signal. The description is omitted.

On the other hand, the failure determination circuit 40 comprises two comparators 42 for comparing the RSSI signal output from the detection / demodulation circuit 30 with the reference voltage Vref1 for determining the presence or absence of reception and the reference voltage Vref2 for determining failure. , 44. Here, when the receiving circuit is operating normally and the receiving antenna 10 is not receiving the transmission radio wave from the external device, the RSSI signal output from the detection / demodulation circuit 30 is added to the reference voltage Vref1. A voltage value is set, and a voltage value lower than this voltage value is set as the reference voltage Vref2.

The comparator 42 compares the RSSI signal with the reference voltage Vref1 to determine whether or not the transmission radio wave from the external device has been normally received. If it is equal to or higher than Vref1, it is determined that the transmission radio wave from the external device has been normally received, and a high-level signal is output.
When the SSI signal is lower than the reference voltage Vref1, it is determined that the transmission radio wave from the external device cannot be normally received, and a low level signal is output. The output from the comparator 42 is input to the data processing circuit at the subsequent stage of the detection / demodulation circuit 30 as a signal presence / absence determination signal.
The data processing circuit executes the processing operation of the received data input from the detection / demodulation circuit 30 only when the reception presence / absence determination signal is at the high level and the transmission radio wave from the external device can be normally received.

The comparator 44 determines whether the receiving circuit is operating normally by comparing the RSSI signal with the reference voltage Vref2.
If the SSI signal is equal to or higher than the reference voltage Vref2, it is determined that the receiving circuit is operating normally, and a high-level signal is output. If the RSSI signal is lower than the reference voltage Vref2, the receiving circuit Judges that a failure has occurred and outputs a low-level signal. The output from the comparator 44 is output as a failure determination signal to an alarm circuit (not shown). When the determination signal is at a low level and the receiving circuit is not operating normally, the user is notified of the fact. To inform.

As described above, in the receiving apparatus according to the present embodiment, unlike the conventional apparatus, a signal for failure diagnosis is not transmitted for failure diagnosis of the receiving circuit.
Using the level detection function of the amplification circuit 32 of the demodulation circuit 30, the signal level of the reception signal input from the reception circuit to the detection / demodulation circuit 30 (specifically, the RSSI signal representing the signal level of the reception signal) The self-diagnosis of the failure of the receiving circuit is performed based on the voltage value).

For this reason, according to the receiving apparatus of the present embodiment,
It is not necessary to provide a transmission circuit or a transmission antenna for transmitting a signal for failure diagnosis, unlike the conventional device, for performing failure diagnosis of the reception circuit, and the failure of the reception circuit can be self-diagnosed with a simple configuration. . Further, in the receiving apparatus of the present embodiment,
In the failure determination circuit 40 as a self-diagnosis means, RS
By comparing the SI signal with the reference voltage Vref2 as a failure determination value, it is possible to not only determine the failure of the receiving circuit but also compare the RSSI signal with the reference voltage Vref1 as the reception presence / absence determination value. It is determined whether or not the transmission radio wave from the external device is normally received, and if the transmission radio wave from the external device is not received, the data processing circuit provided at the subsequent stage of the detection / demodulation circuit 30 is determined. The operation has been stopped.

Therefore, when there is no received signal, the data processing circuit does not needlessly operate, and the power consumption in the receiving device can be reduced. Therefore, if the receiving device of the present embodiment is applied to a portable receiving device, the consumption of the battery (primary battery or secondary battery) used as the driving power source can be suppressed.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
Various embodiments can be adopted. For example, in the above-described embodiment, one failure determination value (reference voltage Vref2) set in advance is used to determine the failure of the receiving circuit. However, for example, the amplification circuit 14 is used as the failure determination value. Determination value Vrefa for the mixer, failure determination value Vrefb for the mixer 18, and failure determination value V when the receiving circuit does not function at all.
refc, a plurality of failure determination values are set in advance, and these failure determination values Vrefa, Vrefb, Vrefc and RS
The details of the failure of the receiving circuit may be determined in more detail by comparing the SI signal with the SI signal. still,
When the above three types of failure determination values Vrefa to Vrefc are set, if the reception circuit does not operate at all, no reception signal is input to the detection / demodulation circuit 30. The determination value Vrefc is set to the smallest voltage value (for example, 0), and when only the mixer 18 fails, the intermediate frequency signal output from the mixer 18 is lower than when only the amplifier circuit 14 fails. Therefore, the failure determination value Vrefa for the amplifier circuit 14 is set to the highest voltage value within a range lower than the reception presence / absence determination value Vref1, and the failure determination value Vrefb for the mixer 18 is set to the failure determination value. What is necessary is just to set the voltage value between the values Vrefa and Vrefc.

Further, in the above embodiment, the failure determination of the receiving circuit is described as being determined by using the comparator. However, the data processing circuit and the like provided at the subsequent stage of the detection / demodulation circuit 30 are constituted by a microcomputer. When a microcomputer is incorporated in the receiving device, a failure determination of the receiving circuit may be performed by a processing operation of the microcomputer.

Further, in the above embodiment, the detection / demodulation circuit 30 is for digital data reception, which generates a binary signal by comparing the received signal with the reference voltage Vref0 by the comparator 38. Although the present invention has been described, it goes without saying that the present invention can be applied to a receiving device that receives an analog signal, such as a radio receiver, in the same manner as in the above embodiment.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an entire receiving apparatus according to an embodiment.

FIG. 2 is a circuit diagram illustrating a configuration of a detection / demodulation circuit and a failure determination circuit according to the embodiment.

FIG. 3 shows the signal level (received level) of a received signal and RS
FIG. 3 is an explanatory diagram illustrating a relationship with an SI signal.

FIG. 4 is a block diagram illustrating a configuration of a conventional receiving device with a self-diagnosis function.

[Explanation of symbols]

10, receiving antenna, 12, 20, BPF (bandpass filter), 14, 32, amplifying circuit, 16, oscillating circuit,
18: mixer, 30: detection / demodulation circuit, 34: detection circuit, 36: LPF (low-pass filter), 38, 42,
44: comparator, 40: failure determination circuit.

Claims (2)

[Claims] A receiving means for receiving a transmission signal from outside; a signal processing means for selecting and outputting a specific reception signal to be detected and demodulated from the reception signals received by the reception means; Detection / demodulation means for detecting / demodulating a reception signal output from the signal selection means and extracting an information signal included in the reception signal; and detecting a failure in a reception system from the reception means to the detection / demodulation means. A self-diagnosis unit for diagnosing, wherein the detection / demodulation unit has a level detection function of detecting a signal level of a reception signal output from the signal selection unit, and the self-diagnosis unit includes: The signal level of the received signal obtained by the level detection function of the detection / demodulation means is compared with a preset failure determination value, and when the signal level of the received signal is lower than the failure determination value. A failure of the receiving system is determined. 2. The self-diagnosis unit compares the signal level of the received signal obtained by a level detection function of the detection / demodulation unit with a plurality of failure determination values set in advance to determine the failure. 2. The receiving apparatus according to claim 1, wherein a failure of each part of the receiving system corresponding to the determination value is determined.