JP4994207B2 - Receiving machine - Google Patents

Description

  The present invention relates to a receiver that mixes an externally received signal and a local frequency signal by a mixer to generate an intermediate frequency signal, and demodulates the generated intermediate frequency signal. The present invention relates to a receiver capable of performing a self-diagnosis test for determining whether or not it is operating.

  Conventionally, in a wireless communication receiver mounted on a ship or the like, whether or not the receiver is operating normally, that is, whether or not the receiver is able to normally receive a received signal from the outside. Judgment self-diagnosis tests are performed as appropriate. In this self-diagnosis test, first, a harmonic test signal obtained by multiplying a signal having a lower frequency (for example, 10 kHz) than the frequency of a received signal (for example, a distress signal for ships in the MF band of 2 MHz to 16 MHz or the HF band). And the test signal is input to the mixer instead of the received signal. The mixer mixes the test signal and a local frequency signal to generate an intermediate frequency signal (IF signal), and a level detector detects the IF signal amplified by an AGC (Automatic Gain Control) amplifier. The detected voltage is output to the controller. The controller determines that the receiver is operating normally when the level of the detection voltage exceeds a predetermined level.

  As a receiver having a function of a self-diagnosis test, Patent Document 1 proposes a radio receiver for a pager, and Patent Document 2 proposes a receiver for AM broadcast and FM broadcast by the superheterodyne system. Has been.

JP-A-7-131429 JP 2005-303650 A

  By the way, in the receiver, the IF signal amplified by the AGC amplifier is demodulated by the demodulator to generate the demodulated signal, and the modulated signal in the received signal is taken out. Therefore, the receiver operates normally. In order to determine whether or not there is a self-diagnostic test, it is desirable to perform a self-diagnosis test on the entire receiver including from the input of the antenna that receives the received signal from the outside to the output of the demodulator.

  However, in the receiver according to the prior art, it is determined whether or not the receiver is operating normally based on the level of the detection voltage corresponding to the IF signal amplified by the AGC amplifier. Self-diagnostic tests are not performed on the entire receiver including the output of.

  In the receivers of Patent Documents 1 and 2, since the local oscillator that generates the local frequency signal and the test signal generation circuit that generates the test signal are separated, the cost and circuit scale of the receiver increase. Also, in the receiver of Patent Document 2, the IF signal amplified by the AGC amplifier is detected, and based on the level of the detected voltage, whether or not the receiver normally receives the received signal from the outside. Therefore, even in Patent Document 2, a self-diagnosis test is not performed on the entire receiver including the output of the demodulator.

  The present invention has been made in consideration of such problems, and is a receiver capable of realizing both downsizing and cost reduction of a receiver and performing a self-diagnosis test on the entire receiver. The purpose is to provide.

The receiver according to the present invention is:
In a receiver that mixes an externally received signal and a local frequency signal with a mixer to generate an intermediate frequency signal, and demodulates the generated intermediate frequency signal with a demodulator,
A reference oscillator for generating a reference signal, a test signal generator for generating a test signal having a frequency of the received signal by dividing the frequency of the reference signal, and a local for generating the local frequency signal based on the reference signal A receiving local circuit comprising an oscillator;
A signal switching unit that selects and outputs either the received signal or the test signal to the mixer;
The selection of the received signal or the test signal in the signal switching unit and the generation of the local frequency signal in the local oscillator are controlled, and the receiver is based on a test message signal indicating a modulation signal in the received signal. A controller that performs a self-diagnostic test to determine whether the modulation signal is normally received;
Have
Under the control of the controller, the signal switching unit outputs the test signal to the mixer, and the local oscillator generates a local frequency signal corresponding to the test message signal based on the reference signal to the mixer. When outputting,
The mixer mixes the test signal and the local frequency signal corresponding to the test message signal to generate an intermediate frequency signal for the self-diagnosis test,
The demodulator demodulates the intermediate frequency signal for the self-diagnosis test, and outputs the demodulated signal to the controller as a demodulated signal,
The controller determines whether or not the receiver has normally received the modulated signal based on a comparison between the demodulated signal from the demodulator and the test message signal. To do.

  According to the present invention, a reception local circuit is constituted by a reference oscillator, a local oscillator, and a test signal generation unit, and the test signal generation unit divides the frequency of the reference signal generated by the reference oscillator to thereby generate a test signal. On the other hand, the local oscillator generates a local frequency signal corresponding to a test message signal indicating a modulation signal in the received signal based on the reference signal. That is, in the self-diagnosis test, the reception local circuit can generate both the test signal and the local frequency signal corresponding to the test message signal using the reference signal. Therefore, since it is not necessary to provide a test signal generation circuit for self-diagnosis test separately from the reception local circuit, the receiver can be reduced in size and cost.

  Further, the controller determines whether or not the receiver has normally received the modulated signal based on the comparison between the demodulated signal corresponding to the test signal and the test message signal. A self-diagnosis test can be performed.

  As shown in FIG. 1, a receiver 10 according to an embodiment of the present invention includes an antenna input unit 12, a signal switching unit 14, bandpass filters (BPF) 16, 24, amplifiers 18 and 26, a reception local circuit 20, and a mixer. 22, an A / D converter 28, a demodulator 30 and a controller 32. The reception local circuit 20 includes a reference oscillator 34, a DDS (Direct Digital Synthesizer) 40 as a local oscillator, and a test signal generation unit 48 including a frequency divider 36 and a multiplier circuit 38. Further, the controller 32 includes a demodulated signal encoding unit 42, a code data reference unit 44, and a code data storage unit 46.

  In addition, this receiver 10 is mounted on, for example, a ship (not shown), and a reception signal Sr of a predetermined frequency from another ship (for example, in MF band and HF band of 2 MHz, 4 MHz, 6 MHz, 8 MHz, 12 MHz, and 16 MHz). Ship distress signal) can be received via the antenna and the antenna input unit 12.

  Based on the control from the controller 32, the signal switching unit 14 selects either the reception signal Sr (the distress signal) from the antenna input unit 12 or the test signal St from the reception local circuit 20 and outputs it to the BPF 16. To do. The test signal St is a harmonic signal including the frequency of the reception signal Sr.

  The BPF 16 is a filter that can switch the passband frequency of the BPF 16 based on control from the controller 32. In this case, the passband frequencies of the BPF 16 are set to the frequencies (2 MHz, 4 MHz, 6 MHz, 8 MHz, 12 MHz, and 16 MHz) of the reception signal Sr and the test signal St. The amplifier 18 amplifies the reception signal Sr or the test signal St that has passed through the BPF 16 and outputs the amplified signal to the mixer 22.

  The mixer 22 mixes the reception signal Sr or test signal St amplified by the amplifier 18 and the local frequency signal S1 from the reception local circuit 20 to generate an IF signal Si having a predetermined frequency (for example, 40 MHz). The BPF 24 is a filter having a passband frequency of 40 MHz, for example. The amplifier 26 is an AGC amplifier that amplifies the IF signal Si that has passed through the BPF 24 and outputs the amplified signal to the A / D converter 28. The A / D converter 28 converts the IF signal Si amplified by the amplifier 26 from an analog signal to a digital signal and outputs the converted signal to the demodulator 30. The demodulator 30 performs predetermined digital demodulation processing on the IF signal Si converted into a digital signal, and outputs the demodulated signal Sd to the controller 32.

  The reference oscillator 34 of the reception local circuit 20 generates a reference signal So having a predetermined frequency (for example, 20 MHz). The frequency divider 36 of the test signal generator 48 divides the frequency of the reference signal So by, for example, 10 and outputs it to the multiplier circuit 38. The multiplier circuit 38 is an amplifier that multiplies the reference signal So (2 MHz signal) divided by 10 to generate a test signal St that is a 2 MHz harmonic signal and outputs the test signal St to the signal switching unit 14. As described above, since the received signal Sr is a distress signal of 2 MHz, 4 MHz, 6 MHz, 8 MHz, 12 MHz, or 16 MHz, the test signal St that is a harmonic signal of 2 MHz is a signal that simulates the received signal Sr. . The DDS 40 generates a local frequency signal Sl based on the frequency data (and code data) stored in the code data storage unit 46 of the controller 32 and the reference signal So, and outputs it to the mixer 22.

  For example, if a signal generated by performing binary FSK modulation processing on predetermined code data (modulated signal of 0 or 1 digital data) is the received signal Sr, the code data storage unit 46 receives the received signal Sr. The frequency data indicating the frequency of the signal Sr and the test signal St and the code data indicating the modulation signal in the reception signal Sr (0 or 1 digital data, also referred to as a test message signal) are stored in advance. ing.

  In the DDS 40, when the reception signal Sr is input to the mixer 22, the frequency of the local frequency signal Sl is set based on the frequency data in the code data storage unit 46 under the control of the controller 32, and the reference signal A local frequency signal S1 having the set frequency is generated based on So. When the test signal St is input to the mixer 22, the DDS 40 sets the frequency of the local frequency signal Sl based on the frequency data under the control of the controller 32, and the reference signal So and the code data are set. Based on the (test message signal), the local frequency signal Sl corresponding to the modulation signal is generated at the set frequency.

  The demodulator 30 performs a predetermined digital demodulation process on the IF signal Si corresponding to the received signal Sr, or the IF signal Si based on the test signal St and the local frequency signal Sl corresponding to the modulation signal, to generate a demodulated signal. Since Sd is generated, if the receiving function of the receiver 10 is normal, the demodulated signal Sd indicates the modulated signal. Therefore, it can be said that the code data is digital data corresponding to the demodulated signal Sd.

  The controller 32 controls the signal switching unit 14 so as to output the reception signal Sr to the BPF 16, controls the BPF 16 so as to have a passband frequency corresponding to the frequency of the reception signal Sr, and stores the code data storage unit 46. By controlling the DDS 40 to generate the local frequency signal Sl based on the frequency data and the reference signal So, the demodulated signal Sd is generated from the received signal Sr, that is, the modulated signal is extracted from the received signal Sr. Next, the entire receiver 10 is controlled.

  Further, the controller 32 controls the signal switching unit 14 so as to output the test signal St to the BPF 16, controls the BPF 16 to have a passband frequency corresponding to the frequency of the test signal St, and the code data storage unit 46. By controlling the DDS 40 so as to generate the local frequency signal Sl based on the frequency data and code data therein and the reference signal So, whether or not the receiver 10 is operating normally, that is, the receiver 10 Performs a self-diagnosis test to determine whether or not the modulation signal is normally received.

  The demodulated signal encoding unit 42 encodes the demodulated signal Sd and outputs it to the code data reference unit 44. The code data reference unit 44 refers to the code data from the demodulated signal encoding unit 42 and the code data in the code data storage unit 46, and if the code data match, the received signal Sr in the receiver 10 Is determined to be normal (the receiver 10 has received the modulated signal normally).

  In the receiver 10, the reception signal Sr from the antenna input unit 12 is normally input to the mixer 22 via the signal switching unit 14, the BPF 16 and the amplifier 18. In the DDS 40, the reference signal So and the code data storage unit are input. A local frequency signal Sl is generated based on the frequency data from 46, and this local frequency signal Sl is input to the mixer 22. The mixer 22 mixes the reception signal Sr amplified by the amplifier 18 and the local frequency signal Sl to generate an IF signal Si, and outputs the IF signal Si to the demodulator 30 via the BPF 24, the amplifier 26 and the A / D converter 28. To do. The demodulator 30 demodulates the IF signal Si converted into a digital signal by the A / D converter 28 to generate a demodulated signal Sd.

  On the other hand, when performing a self-diagnosis test in the receiver 10, the signal switching unit 14 is controlled to output the test signal St to the BPF 16 by the control from the controller 32, and according to the frequency of the test signal St. The BPF 16 is controlled to have a passband frequency, and the DDS 40 is controlled to have a local frequency signal Sl based on the frequency data, the code data, and the reference signal So. Thereby, instead of the reception signal Sr, the test signal St is input to the mixer 22 via the signal switching unit 14, the BPF 16, and the amplifier 18, and in the DDS 40, based on the reference signal So, the frequency data, and the code data. Thus, a local frequency signal Sl is generated, and this local frequency signal Sl is input to the mixer 22. The mixer 22 mixes the test signal St amplified by the amplifier 18 and the local frequency signal Sl to generate an IF signal Si, and outputs the IF signal Si to the demodulator 30 via the BPF 24, the amplifier 26 and the A / D converter 28. To do. The demodulator 30 demodulates the IF signal Si converted into a digital signal by the A / D converter 28 to generate a demodulated signal Sd.

  The demodulated signal encoding unit 42 encodes the demodulated signal Sd, and the code data reference unit 44 refers to the code data from the demodulated signal encoding unit 42 and the code data in the code data storage unit 46, and If the respective code data match, it is determined that the receiver 10 has received the modulated signal normally.

  As described above, according to the receiver 10 according to this embodiment, the reception local circuit 20 is configured by the reference oscillator 34, the DDS 40, and the test signal generation unit 48, and the test signal generation unit 48 is used in the self-diagnosis test. Generates a test signal St by dividing the frequency of the reference signal So generated by the reference oscillator 34 by the frequency divider 36 and multiplying the frequency by the multiplier circuit 38, while the DDS 40 generates the reference signal So. The local frequency signal Sl is generated based on the frequency data and the code data (test message signal) in the code data storage unit 46. That is, the reception local circuit 20 can generate both the test signal St and the local frequency signal Sl corresponding to the code data using the reference signal So.

  Therefore, in the receiver 10, it is not necessary to provide a test signal generation circuit for self-diagnosis test separately from the reception local circuit 20, and further, a test signal generation unit configured simply by the frequency divider 36 and the multiplier circuit 38. Since the test signal St is generated by 48, the receiver 10 can be reduced in size and cost.

  In addition, the code data reference unit 44 of the controller 32 includes code data based on the demodulated signal Sd corresponding to the test signal St from the demodulator 30 and the received signal Sr stored in the code data storage unit 46 for self-diagnosis test. Since it is determined whether or not the receiver 10 has normally received the modulated signal based on the comparison with the code data indicating the modulated signal in the receiver, the receiver 10 as a whole can perform a self-diagnosis test. Become.

  In the above description, as an example, the case where the reception signal Sr is generated by performing the binary FSK modulation process on the modulation signal has been described. However, the reception signal Sr generated by another modulation method is described below. In addition, the receiver 10 according to this embodiment is applicable.

  Of course, the present invention is not limited to the above-described embodiment, and may employ various configurations.

It is a block diagram of the receiver concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Receiver 12 ... Antenna input part 14 ... Signal switching part 16, 24 ... BPF
18, 26 ... Amplifier 20 ... Reception local circuit 22 ... Mixer 28 ... A / D converter 30 ... Demodulator 32 ... Controller 34 ... Reference oscillator 36 ... Frequency divider 38 ... Multiplier circuit 40 ... DDS
42 ... Demodulated signal encoding unit 44 ... Code data reference unit 46 ... Code data storage unit 48 ... Test signal generation unit

Claims (1)

In a receiver that mixes an externally received signal and a local frequency signal with a mixer to generate an intermediate frequency signal, and demodulates the generated intermediate frequency signal with a demodulator,
A reference oscillator for generating a reference signal, a test signal generator for generating a test signal having a frequency of the received signal by dividing the frequency of the reference signal, and a local for generating the local frequency signal based on the reference signal A receiving local circuit comprising an oscillator;
A signal switching unit that selects and outputs either the received signal or the test signal to the mixer;
The selection of the received signal or the test signal in the signal switching unit and the generation of the local frequency signal in the local oscillator are controlled, and the receiver is based on a test message signal indicating a modulation signal in the received signal. A controller that performs a self-diagnostic test to determine whether the modulation signal is normally received;
Have
Under the control of the controller, the signal switching unit outputs the test signal to the mixer, and the local oscillator generates a local frequency signal corresponding to the test message signal based on the reference signal to the mixer. When outputting,
The mixer mixes the test signal and the local frequency signal corresponding to the test message signal to generate an intermediate frequency signal for the self-diagnosis test,
The demodulator demodulates the intermediate frequency signal for the self-diagnosis test, and outputs the demodulated signal to the controller as a demodulated signal,
The controller determines whether or not the receiver has normally received the modulated signal based on a comparison between the demodulated signal from the demodulator and the test message signal. Receiver.

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