JP2010130217A - Radio signal reporting apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio signal reporting apparatus, capable of employing, as a circuit configuration of a receiving section, a cost-saving typical configuration in a manner similar to those of conventional apparatuses and preventing malfunctions in a strong electric field area, such as, in the vicinity of a transmission station. <P>SOLUTION: The radio signal reporting apparatus includes a receiving section 1, a signal level detecting section 2, an operation section 3, a reporting section 4, a scan frequency setting section 5, a storage section 6, etc., and is configured to receive the radio waves of a band at 150 to 470 MHz and to output a report signal, in response to a signal level of target radio waves which are equal to or higher than a prescribed level. Frequencies of the band to be received and monitored are allocated to a car locator system, a jurisdiction digital radio system, etc. Frequencies close to that of the target radio waves are also received by an indication of the scan frequency setting section 5. When the signal level of the target radio waves is equal to or higher than the prescribed level, the operation section 3 call a driver's attention and performs the operation of reducing reception sensitivity in the case that a signal level at the close frequencies also is equal to or higher than the prescribed level. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio signal notification device and a program for receiving a radio wave in a specific frequency band and outputting a notification signal when a signal level of a target radio wave is equal to or higher than a predetermined level. More specifically, the present invention relates to a received radio signal. The present invention relates to an improvement in determination operation for determining authenticity.

  The radio signal notification device that is the subject of the present invention is a so-called radio receiver that is installed in a vehicle or the like, receives radio waves in a specific frequency band, and outputs a notification signal when the signal level of the target radio wave is equal to or higher than a predetermined level. It is like that. This is configured to receive radio waves in a band from 150 MHz to 470 MHz, and these frequencies are assigned to a car locator system, a jurisdiction digital radio, and the like.

  Specifically, the car location system (hereinafter referred to as “car location radio”) is a system for dynamically grasping the current position of an emergency vehicle, and this is based on the position information from the moving emergency vehicle being 407.725 MHz. The communication command headquarters that receives the position information data transmits the data in real time and displays the position on the map screen in real time. Therefore, since the radio signal notification apparatus monitors the carrier wave (407.725 MHz) of the car location radio, by detecting whether or not such an emergency vehicle exists in the vicinity, the emergency vehicle travel is not hindered. It can be used for safe driving.

  As shown in FIG. 1, in the radio signal notification apparatus, the receiving unit often employs a superheterodyne system and is configured to perform frequency conversion in two stages in order to separate the image frequency. In the first stage of the receiving unit, band-pass filters (BPF) 11 and 12 are provided without the high-frequency amplifier, and excess signals from the radio waves received from the antenna 10 are attenuated by the BPFs 11 and 12 and removed. Is also often adopted.

  By the way, in the receiving unit as shown in FIG. 1, since the circuit is non-linear, the output signal always includes harmonics, intermodulation distortion and other spurious components, which is a factor of performance degradation. Therefore, the receiving unit shown in FIG. 1 has a practically sufficient level of receiving performance by performing tuning such as optimizing circuit constants.

  However, in the vicinity of transmitting stations such as televisions and radios, the radio waves generated by the transmissions become strong electric fields, so that the receiving unit receives interference due to cross modulation (intermodulation), image interference, sensitivity suppression, etc., causing malfunctions. There is. In particular, it may differ depending on the frequency at which the third harmonic product appears, but it may be erroneously detected as reception of the target radio wave being monitored. This is because the selectivity performance of the typical superheterodyne circuit configuration shown in FIG. 1 is moderate, and is unavoidable in strong electric field areas such as the vicinity of the transmitting station. There is a fact that the demand for improvement is not so high because it occurs in a narrow area and is resolved when a traveling vehicle passes through the area.

  However, in recent years, as is well known, transmission stations have been expanded throughout the country due to the full-scale digital terrestrial broadcasting. For this reason, with the increase in the number of transmitting stations, the number of places where malfunctions occur in various parts of the country has increased, and the demand for improvement has increased. The source of the strong electric field is not limited to the transmitting station of the broadcasting station, but since so-called broadcasting stations have many relay stations and transmitting stations all over the country, they will pass nearby while moving on the road. There are many opportunities, and it can be said that the transmission output is large and the influence is large compared with various types of commercial radio stations.

  Terrestrial digital broadcasting is divided into 13 channels to 62 channels from 473.142857 MHz to 767.142867 MHz every 6 MHz steps, and the transmission output is about one-tenth of analog waves because digital waves have good propagation characteristics. The output can be reduced, and for example, transmission is performed at an output of about 10 kW. However, even if the transmission output is about 10 kW, it is certain that the electric field is strong when passing in the vicinity, causing interference to the receiving unit and causing a reception failure.

  Therefore, as a countermeasure, in order to increase the selectivity of the receiving unit, there is an idea that the first-stage BPFs 11 and 12 have sharp cutoff characteristics and high attenuation characteristics, and are configured to greatly attenuate the band other than the target radio wave so as not to pass. However, in strong electric field areas, radio waves are not always input from the antenna 10, and there are harmonic components that jump directly into each part of the circuit. Therefore, even if the BPFs 11 and 12 in the first stage are unnecessarily high in performance, interference is prevented. Can not. Further, considering that BPFll and 12 have good cutoff characteristics and attenuation characteristics, the cost increases, and considering that there is a harmonic component that jumps directly into each part of the circuit, this is not an effective measure.

  Therefore, in the vicinity of the terrestrial digital broadcasting transmitting station, the first-stage bandpass filters (BPF) 11 and 12 of the receiving section shown in FIG. 1 cannot attenuate the terrestrial digital broadcasting radio waves, and take them into the first mixer. End up.

On the other hand, in the circuit shown in FIG. 1, in order to detect the target radio wave, frequency scanning is performed to automatically scan tuning for a predetermined frequency band. For this reason, a frequency signal in a predetermined frequency band is oscillated from a local oscillator and sent to the first mixer for mixing. The first intermediate frequency is set to 20.8 MHz, for example. The output detects 20.8 MHz which is the first IF frequency in the BPF.
a 175.1875-191.5250MHz
b 214.26525-224.0187 MHz
c 30.3750-383.0500 MHz
d 428.5250-448.374 MHz

  These frequencies are used to receive a plurality of types of radio waves (such as car location radio and jurisdiction digital radio).

  As a specific example, when the target radio wave is a car location radio, the frequency is 407.725 MHz, so the local oscillator oscillates 428.5250 MHz (within the above d) including the first IF frequency. This is obtained by doubling the oscillation frequency 214.2625 MHz of VCO2. However, at this time, an undesired harmonic exists in the output of the local oscillator, the third harmonic becomes 642.7875 MHz, and the frequency at which the first intermediate frequency 20.8 MHz is established in the mixing by the first mixer is 663.5875 MHz. And 6211.9875 MHz.

  These frequencies correspond to the frequency range of terrestrial digital broadcasting, 663.5875 MHz is in the band of 45 channels, 621.9875 MHz is in the band of 38 channels, and received in strong electric field areas where radio waves are strong, such as near the transmitting station, There is a problem in that it is indistinguishable from the target radio wave and erroneous notification (malfunction) occurs when the target radio wave is received.

Therefore, as a countermeasure against malfunction due to radio waves of terrestrial digital broadcasting, for example, when checking the location radio, each proximity frequency is checked, and if there is reception of the proximity frequency, A method of prohibiting all notifications in the same frequency band (UHF band) is conceivable (Patent Document 1).
JP 2008-270866 A

  However, if all notifications are prohibited in this manner, no notification is made despite the target radio wave being emitted.

In addition, for example, the car location radio is informing so as not to hinder the travel of the emergency vehicle at the time of reception, but if all the notifications are prohibited, such notification cannot be made, Unable to encourage safe driving.
As described above, there are various purposes for receiving notification of the target radio wave, but there is a problem that appropriate notification in accordance with the purpose cannot be performed.

  The object of the present invention is to solve the above-described problems. The purpose of the circuit configuration of the receiving unit is to adopt a typical configuration in which the cost is reduced as in the conventional case, and in a strong electric field area such as the vicinity of the transmitting station. A radio signal that can be used for the purpose of receiving and notifying the target radio wave, such as being able to prevent malfunctions and alerting the driver not to hinder the driving of emergency vehicles. It is to provide a notification device and a program.

  (1) In order to achieve the above-described object, the radio signal notification device according to the present invention includes a receiving unit for receiving a target radio wave in a specific frequency band such as 150 MHz to 470 MHz, and the target with respect to the receiving unit. A frequency setting unit that sets a frequency according to a radio wave; a signal level detection unit that detects a signal level of the radio wave received by the reception unit; and reception of a target radio wave when the signal level of the target radio wave is equal to or higher than a predetermined value. A calculation unit that outputs a signal for notification related to, and the reception unit also receives a determination frequency set in association with the target radio wave according to an instruction from the frequency setting unit, and the calculation unit includes: A radio signal notification device that does not output a signal for notification related to reception of the target radio wave when a signal level at the determination frequency is equal to or higher than a predetermined level. , The arithmetic unit, a configuration in which the signal level at the determined frequency to output a signal for informing about that poor reception condition of the target radio wave when the predetermined or more.

  The “predetermined level” of the determination criterion for discriminating the presence or absence of the target radio wave and the “predetermined level” of the determination criterion for discriminating the presence or absence of the radio wave of the determination frequency may be different or the same. Usually, since the radio wave of the determination frequency that causes an erroneous determination is larger than the true target radio wave to be detected, the threshold value of the “predetermined level” of the signal level of the determination frequency may be set higher.

  If a radio wave with a determination frequency set in association with the target radio wave such as a frequency close to the target radio wave frequency or a specific frequency is received and a radio wave with a level higher than a predetermined level is received, the true target to be detected Even if no radio wave exists, a signal having a frequency of the target radio wave may be received due to the received radio wave. Therefore, when the signal level of the target radio wave is equal to or higher than a predetermined value, a signal for notification regarding reception of the target radio wave is not output, but the arithmetic unit does not output when the signal level at the determination frequency is higher than the predetermined level. Outputs a signal for notifying that the reception state of the target radio wave is bad.

  Therefore, by not outputting a signal for notification related to reception of the target radio wave, no notification is made even though the target radio wave is emitted.

  (2) In particular, it is preferable to provide a notification unit that performs notification that alerts the driver based on a signal for notification regarding poor reception of the target radio wave. In this way, the driver can be alerted even in situations where the target radio wave reception is poor.

  Note that the determination frequency set in association with the target radio wave may be a unique frequency that affects the target radio wave, an adjacent channel frequency, or unique channel information. Further, reception of the determination frequency set in association with the target radio wave may be performed by frequency scanning for each predetermined step. The detection of the target radio wave and the radio wave of the determination frequency may be performed by configuring each with an independent receiving unit.

  (3) In addition, the calculation unit may replace the determination frequency instead of outputting a signal for notifying that the reception state of the target radio wave is bad when the signal level at the determination frequency is equal to or higher than a predetermined level. When the signal level at is higher than a predetermined level, the receiving sensitivity of the receiving unit may be attenuated. (That is, it is not essential for the arithmetic unit to output a signal for notifying that the reception state of the target radio wave is bad when the signal level at the determination frequency is equal to or higher than a predetermined level.) The calculation unit outputs a signal for notifying that the reception state of the target radio wave is bad when the signal level at the determination frequency is equal to or higher than a predetermined level, and the signal level at the determination frequency is higher than the predetermined level. In this case, the receiving sensitivity of the receiving unit may be attenuated.

In this way, when the signal level at the determination frequency is equal to or higher than the predetermined level, the signal level detection unit detects the signal level in a state where the reception sensitivity of the reception unit is attenuated. When the signal level at the determination frequency in the attenuated state is less than a predetermined value, the calculation unit outputs a signal for notification related to reception of the target radio wave.
Therefore, it is possible to reduce the state in which a signal for notification related to reception of the target radio wave is not output. Therefore, it is possible to perform appropriate notification in accordance with the purpose of receiving notification of the target radio wave.

  (4) Furthermore, when the signal level at the determination frequency is equal to or higher than a predetermined level, the reception sensitivity of the reception unit is set to an attenuation state, and after a predetermined time, the reception sensitivity attenuation state of the reception unit is canceled, and after the release If the signal level at the determination frequency is less than a predetermined value, the attenuation of the reception sensitivity is canceled. On the other hand, if the signal level at the determination frequency after the cancellation is equal to or higher than the predetermined level, the attenuation state is again set. As described above, when the signal level at the determination frequency is equal to or higher than a predetermined level, it is preferable not to output a signal for notification related to reception of the target radio wave.

  In this way, when the attenuation state of the reception sensitivity of the receiving unit is canceled after a predetermined time, if the signal level at the determination frequency is less than the predetermined, the attenuation of the reception sensitivity is canceled, At this time, if the signal level of the target radio wave is equal to or higher than a predetermined level, a signal for notification related to reception of the target radio wave is output. If the signal level at the determination frequency is greater than or equal to a predetermined value when the reception sensitivity attenuation state of the receiving unit is canceled after a predetermined time, the signal level at the determination frequency is still greater than or equal to the predetermined value. In some cases, a signal for notification related to reception of the target radio wave is not output. Therefore, malfunction (false alarm) can also be suppressed. Therefore, it is possible to perform appropriate notification in accordance with the purpose of receiving notification of the target radio wave.

The determination frequency may be a frequency close to the frequency of the target radio wave, or may be a frequency related to the target radio wave, and various settings can be made. That is, how to fix the target radio wave, the determination frequency, and the frequency of the jamming radio wave will be described in detail. First, each condition is as follows.
Target radio wave Fire fighting radio: 466.4125MHz
Interfering radio wave mobile phone base station: 870.0250-884.950MHz
IF frequency: 20.8MHz
Local oscillation frequency for target radio wave reception: 445.6125 MHz
(222.80625MHz × 2)
Judgment frequency for receiving jamming radio waves: 870.425 MHz
(222.80625MHz × 4-20.8MHz)

  In the above case, the harmonic of 4 times the local oscillation frequency for receiving the target radio wave is included in the frequency range of the mobile phone base station. In this case, the proximity frequency may be used as the determination frequency, but since the quadruple wave is not originally generated intentionally, an appropriate determination cannot be made only by the determination of the proximity frequency due to variations in oscillation level intensity or the like. . In such a case, an appropriate determination can be made by generating a quadruple wave and receiving the original frequency of the original mobile phone base station as the determination frequency.

  The determination frequency set in association with the target radio wave can be a specific frequency that affects the target radio wave, an adjacent channel frequency, or specific channel information. Associating with the target radio wave, frequency information corresponding to the target radio wave may be separately provided on the memory, or the adjacent frequency may be viewed on the program.

  Reception of the determination frequency set in association with the target radio wave may be performed by frequency scanning for each predetermined step. Furthermore, when the target radio wave is in a single operation mode that is not assigned to frequency scanning for each predetermined step, the determination frequency may be set to a unique frequency.

  (5) The function of the radio signal notification device can be configured as a program for causing a computer to realize the function. For example, it may be configured as a program for processing in a microcomputer or the like.

  The circuit configuration of the receiving unit can take a typical configuration with reduced cost as in the past, and it can prevent malfunction in strong electric field areas such as the vicinity of the transmitting station and does not hinder the traveling of emergency vehicles. For example, the driver can be further alerted, and more appropriate notification can be made in accordance with the purpose of receiving the target radio wave.

  FIG. 2 shows a preferred embodiment of the present invention. In this embodiment, the radio signal notification device includes a reception unit 1, a signal level detection unit 2, a calculation unit 3, a notification unit 4, a scan frequency setting unit 5, a storage unit 6, and the like, and receives radio waves in a specific frequency band. Thus, an alarm signal is output when the signal level of the target radio wave is equal to or higher than a predetermined level. The band for reception monitoring is a band from 150 MHz to 470 MHz. These frequency bands are allocated to car locator systems, jurisdiction digital radios, and the like.

  As shown in FIG. 3, the receiving unit 1 includes an attenuator for attenuating the signal input to the antenna 10 in addition to the configuration shown in FIGS. 1 and 2, and the attenuation signal from the arithmetic unit 3 is turned on. In this case, a two-stage superheterodyne system is provided, which further includes an attenuator control unit 20 that is attenuated (attenuator ON) and is not attenuated (attenuator OFF) when the attenuation signal from the calculation unit 3 is OFF. The jurisdiction digital radio uses a frequency of 347.7125 MHz to 348.2125 MHz and 361.1 MHz to 362.25 MHz separately for each 12.5 kHz step. In this case, the receiver 1 (receiver shown in FIG. 3) converts the frequency to the first intermediate frequency (20.8 MHz) by the first mixer 13 and converts the frequency to the second intermediate frequency (450 kHz) by the second mixer 14. However, the band pass filter (BPF) following the second mixer 14 has a pass band width of ± 12.5 kHz centered at 450 kHz, and is configured to block reception of neighboring channels by band limitation.

  Frequency scanning is performed for radio wave reception, and the specific frequency band described above is monitored by automatic frequency switching. The received radio wave signal is detected by the signal level detection unit 2 and the signal level is inspected by the calculation unit 3 to determine the signal intensity level of the target frequency and the determination frequency.

  In the frequency scan operation, as shown in FIG. 4, first, a nearby channel that is approaching the target radio wave is instructed from the scan frequency setting unit 5 to the reception unit 1 (S1), and the signal level (RSSI voltage) is received. An inspection is performed (S2). The RSSI voltage is a signal level of a received radio wave and may be considered as an electric field strength. Here, when the RSSI voltage of the neighboring channel exceeds a predetermined value, the neighboring channel is determined as “received” (S3), and when not exceeded, it is determined as “non-received” (S4). The determination state of this neighboring channel is stored in the storage unit 6.

  Next, the target radio wave is instructed from the scan frequency setting unit 5 to the receiving unit 1 and received (S5), and the signal level (RSSI voltage) is inspected (S6). Here, when the RSSI voltage of the target radio wave exceeds a predetermined value, the target radio wave is determined to be “received” (S7), and otherwise, it is determined to be “non-received” (S8). The determination state of the target radio wave is stored in the storage unit 6.

  Then, the determination state of the neighboring channel and the determination state of the target radio wave are inspected (S9). Here, if the target radio wave is “reception” (S6: reception) and the neighboring channel is “non-reception” (0 in S9), it is determined as true reception, and a flag (predetermined usable in subsequent processing, etc.) The variable value or the like is set to “true reception” (S10), and a notification signal indicating true reception is output to the notification unit 4 (S11). If the target radio wave is “non-received” (S6: non-received) and the neighboring channel is “non-received” (0 in S15), it is determined as non-received and the flag is set to “non-received” (S16). Does not output an attenuation signal. If the above condition is not satisfied, it is determined that the reception is false, the flag is set to “false reception” (S12), a notification signal indicating false reception is output to the notification unit 4 (S13), and attenuator control is performed. The attenuation signal to the unit 20 is turned on (S14). In either case, after that, the process returns to the top of the processing routine for the next frequency scan.

  When a frequency scan break, for example, every scan requires a second, the reception attenuation unit determination control shown in FIG. 5 is started every a second. First, the determination frequency is instructed from the scan frequency setting unit 5 to the reception unit 1 and received, and the attenuation signal is turned OFF (attenuator OFF) (S17). Subsequently, the signal level (RSSI voltage) is inspected (S18). Here, when the RSSI of the determination frequency does not exceed the predetermined value, it is determined as “non-reception” (S19), and the attenuation signal is turned OFF (attenuator OFF) (S20). Thereafter, the frequency scan (FIG. 4) is executed with the attenuator OFF (without attenuation).

  On the other hand, when the RSSI of the determination frequency exceeds a predetermined value, it is determined as “reception” (S21), and the attenuation signal is turned ON (attenuator ON) (S22). Thereafter, the frequency scan (FIG. 4) is executed with the attenuator ON (attenuated) until it is determined as “not received” at the determination frequency.

  That is, in the execution of the determination operation described above, the signal level state shown in FIG. 6A is determined as “false reception” when the neighboring channel is “reception” and the target radio wave is “reception”. The signal level state shown in FIG. 6B is determined as “false reception” when the neighboring channel is “reception” and the target radio wave is “non-reception”. The state is determined as “true reception” when the neighboring channel is “non-reception” and the target radio wave is “reception”. The signal level state shown in FIG. 6D is determined as “non-reception” when the neighboring channel is “non-reception” and the target radio wave is “non-reception”. In “true reception”, a notification signal indicating that the signal is a true reception signal is output to the notification unit 4. In “false reception”, a notification signal indicating that the signal is a false reception signal is output to the notification unit 4. Set the attenuation signal to ON. Does nothing when not receiving.

  In addition, 350.1 MHz and 407.725 MHz are frequencies that are operated independently, and have an operation mode in which there is no channel assignment near either the upper side or the lower side of the frequency. When the target radio wave is such a single operation, a dummy channel is set on the side lower than the target radio wave, and the dummy channel is set in the scan frequency setting unit 5 to execute the frequency scan operation.

  In that case, in the execution of the determination operation, the signal level state shown in FIG. 7A is determined as “false reception” when the dummy channel is “reception” and the target radio wave is “reception”. The signal level state shown in FIG. 7B is determined as “false reception” when the dummy channel is “reception” and the target radio wave is “non-reception”. The state of the signal level shown in FIG. 7C is determined as “true reception” when the dummy channel is “non-reception” and the target radio wave is “reception”. The signal level state shown in FIG. 7D is determined as “non-reception” when the dummy channel is “non-reception” and the target radio wave is “non-reception”. In “true reception”, a notification signal indicating that the signal is a true reception signal is output to the notification unit 4. In “false reception”, a notification signal indicating that the signal is a false reception signal is output to the notification unit 4. Set the attenuation signal to ON. Does nothing when not receiving.

  Specifically, a determination operation in reception using a dummy channel will be described by taking as an example a case where the target radio wave is a car location radio (407.725 MHz). In the car location radio, the carrier wave is 407.725 MHz, and there is no assigned channel in the neighborhood, and the carrier is operated at a single frequency. Therefore, a dummy channel is set near the lower side of the target radio wave. For example, the frequency of the dummy channel is set to 407.750 MHz. This is a setting that is about 25 kHz away from the target radio wave (407.725 MHz), and needs to be set outside the BPF passband (± 12.5 kHz) in the second intermediate frequency circuit described above. There is.

  As shown in FIG. 8, in the frequency scan operation, first, a dummy channel (407.750 MHz) approaching the target radio wave is instructed from the scan frequency setting unit 5 to the reception unit 1 and received (d1). (RSSI voltage) is inspected (d2). Here, when the RSSI voltage (VLv) of the dummy channel exceeds a predetermined value (determination RSSI voltage), the dummy channel is determined to be “received” (d3), and if not, it is determined to be “non-received”. (D4). The determination state of the dummy channel is stored in the storage unit 6. The determination RSST voltage (407 Vth) is set to 469.13 mV.

  Next, the target radio wave (407.725 MHz) is received from the scan frequency setting unit 5 by instructing the receiving unit 1 (d5), and the signal level (RSSI voltage) is inspected (d6). Here, when the RSSI voltage (VLv) of the target radio wave exceeds a predetermined value (determination RSSI voltage), the target radio wave is determined as “received” (d7), and otherwise, it is determined as “non-received”. (D8). The determination state of the target radio wave is stored in the storage unit 6.

  Then, the determination state of the dummy channel and the determination state of the target radio wave are inspected (d9). Here, if the target radio wave is “received” (d6: received) and the neighboring channel is “not received” (0 in d9), it is determined as true reception, and a flag (predetermined usable in subsequent processing, etc.) The variable value etc.) is set to “true reception” (d10), and a notification signal indicating true reception is output to the notification unit 4 (d11). When the target radio wave is “not received” (d6: not received) and the neighboring channel is “not received” (0 at d15), it is determined that the signal is not received, the flag is set to “not received” (d16), Does not output an attenuation signal. If the above conditions are not satisfied, it is determined that the reception is false, the flag is set to “false reception” (S12), a notification signal indicating false reception is output to the notification unit 4 (d13), and the attenuator control unit The attenuation signal to 20 is turned ON (d14). In either case, after that, the process returns to the top of the processing routine for the next frequency scan.

  It takes 8 seconds to receive all channels in the frequency scan, and the reception attenuation determination control at the determination frequency is started every 8 seconds. In the case of car location radio, the car location dummy process (an example of the process in FIG. 5) shown in FIG. 9 is started every 8 seconds.

  The car location dummy channel (407.750 MHz) is received from the scan frequency setting unit 5 shown in FIG. 2 to the receiving unit 1 (d17), and the signal level (RSSI voltage) is inspected (d18). At this time, the attenuation signal is turned off and the attenuator is turned off for the reception unit 3 from the calculation unit 3 in FIG.

Here, when the RSSI voltage (VLv) of the dummy channel does not exceed the predetermined value (determination RSSI voltage), it is determined as “non-reception” (d19), and the attenuation signal is turned OFF (attenuator OFF) (d20). Thereafter, the frequency scan (FIG. 8) is executed with the attenuator OFF (not attenuated).
On the other hand, when the RSSI of the determination frequency exceeds a predetermined value, it is determined as “reception” (d21), the attenuation signal is turned on, and the attenuator is continuously turned on (d22).

  That is, in the execution of the determination operation described above, the signal level state shown in FIG. 10A is “fake reception” when the dummy channel 407.750 MHz is “reception” and the target radio wave 407.725 MHz is “reception”. The signal level state shown in FIG. 10B is determined as “false reception” when the dummy channel 407.750 MHz is “reception” and the target radio wave 407.725 MHz is “non-reception”. . The signal level state shown in FIG. 10C is determined as “true reception” when the dummy channel 407.750 MHz is “non-reception” and the target radio wave 407.725 MHz is “reception”. The signal level state shown in FIG. 10D is determined as “non-reception” when the dummy channel 407.750 MHz is “non-reception” and the target radio waves 407 and 725 MHz are “non-reception”. In “Reception”, a notification signal indicating that it is a true reception signal is output to the notification unit 4. In “Fake reception”, a notification signal indicating that it is a false reception signal is output to the notification unit 4 and the attenuation signal is turned on. And Does nothing when not receiving.

  That is, in this case, if the target radio wave (407.725 MHz) is truly received, the dummy channel should not receive. If the dummy channel receives more than a predetermined level, other powerful radio signals such as terrestrial digital broadcasts may be received. You may think that you are receiving. That is, terrestrial digital broadcasting has a radio wave band of 6 MHz. In this case, the dummy channel is also covered and reception occurs. Further, when the signal level of the dummy channel is low, it may be considered that the radio wave generation source is at a long distance because reception of the radio wave is weak.

  In this way, when there is a strong radio wave at a frequency (dummy channel, neighboring channel) close to the target radio wave, it may be considered that there is radio wave reception because it is located in a strong electric field area, etc. Even if the signal level of the target radio wave is above a certain level, it is determined that it is a “fake reception”, so it is possible to prevent malfunctions in strong electric field areas such as the vicinity of the transmitting station and to make the driver of the vehicle even more Can call attention.

  According to the radio signal notification device of the present embodiment, when the reception level of the frequency in the vicinity of the target radio wave is inspected or higher than a predetermined level, the current reception state is receiving another strong radio wave It can be determined whether or not. In other words, even if the signal level of the target radio frequency band is higher than the specified level, or if the signal level is higher than the specified level at nearby frequencies, it may be considered that another strong radio signal such as terrestrial digital broadcasting is being received. In this case, the driver can alert further emergency vehicles and the like. At this time, as a matter of course, the circuit configuration of the receiving unit can adopt a typical configuration with reduced cost as in the conventional case.

  When it is determined that the signal strength of the determination frequency is greater than or equal to a predetermined value and the attenuator of the receiving unit 1 is operated, the signal strength of the determination frequency is confirmed by stopping the attenuator of the wireless reception circuit after a certain period of time has elapsed. If the signal strength is less than the predetermined value as a result of the confirmation, the attenuator is stopped and radio reception is continued. On the other hand, as a result of confirmation, if the signal strength of the determination frequency is equal to or higher than a predetermined value, the operation of the attenuator is continued.

The attenuator is activated when the signal strength of the determination frequency is greater than or equal to a predetermined value. However, if the signal strength of the determination frequency is still greater than or equal to the predetermined value, a further attenuator may be activated, or the determination with reception detection at the target frequency is discarded You may do it.
The signal intensity level of the determination frequency may be measured, and the attenuator may be controlled in accordance with a determination criterion stored in advance in the memory.

  When it is determined that the signal strength of the determination frequency is equal to or greater than a predetermined value, when the attenuator of the receiving unit 1 is operated and the determination frequency becomes equal to or less than a predetermined value, if the signal strength of the target frequency is equal to or greater than the predetermined value, reception is detected. The determination operation can be performed.

  In the present embodiment, the notification output (for example, S13 in FIG. 4 and d13 in FIG. 8) of the notification signal when it is determined that the reception is false is the notification content regarding the poor reception state of the target radio wave. However, it is good to make the content of alerting which alerts a driver. For example, the notification unit 4 is configured as a voice synthesizer and a display device, and in the process of d13 in FIG. 8, a notification signal for performing voice synthesis and display of “Please beware of emergency vehicles” to the notification unit 4. Should be output.

  In the present embodiment, when the attenuation signal from the control unit is ON, the attenuator control unit 20 operates the attenuator (attenuator (ATT)) to reduce the reception sensitivity. The reduction method is not limited to this, and various methods can be used. For example, based on the attenuation signal, the first-stage amplifier power supply may be turned off, the gain may be reduced, the mixer local injection level may be lowered, or the circuit may be bypassed using RFSW or the like.

It is a block diagram which shows the conventional receiving part. It is a block diagram of the radio signal alerting | reporting apparatus which concerns on this invention. It is a block diagram which shows the receiving part of embodiment. It is a flowchart of the determination operation | movement in reception of a target electromagnetic wave. It is a flowchart of the attenuation | damping determination operation | movement in reception of a determination radio wave. It is a graph of the signal level in the determination operation | movement using a neighboring channel, (a) to (d) is four examples from which a receiving state differs. It is a graph of the signal level in the determination operation | movement using a dummy channel, (a) to (d) is four examples from which a receiving state differs. It is a flowchart of the determination operation | movement in the reception which used the target radio wave as a car location radio (407.725 MHz). It is a flowchart of the attenuation | damping determination operation | movement in a determination radio wave (407.75MHz). FIG. 9 is a graph of signal levels in the determination operation of FIG. 8, and (a) to (d) are four examples with different reception states.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception part 2 Signal level detection part 3 Computation part 4 Notification part 5 Scan frequency setting part 6 Storage part 10 Antenna 11,12 BPF
13 First mixer 14 Second mixer

Claims (5)

A receiving unit for receiving a target radio wave in a specific frequency band such as 150 MHz to 470 MHz;
A frequency setting unit that sets a frequency according to the target radio wave for the receiving unit;
A signal level detector that detects the signal level of the radio wave received by the receiver;
A calculation unit that outputs a signal for notification related to reception of the target radio wave when the signal level of the target radio wave is equal to or higher than a predetermined level,
The receiving unit also receives a determination frequency set in association with the target radio wave according to an instruction from the frequency setting unit,
The arithmetic unit is a radio signal notification device that does not output a signal for notification related to reception of the target radio wave when a signal level at the determination frequency is a predetermined level or more,
The radio signal notifying device, wherein the arithmetic unit outputs a signal for informing that the reception state of the target radio wave is bad when a signal level at the determination frequency is equal to or higher than a predetermined level. The radio signal notification device according to claim 1, further comprising: a notification unit that performs a notification to call attention to a driver based on a signal for notification regarding poor reception of the target radio wave. The computing unit may instead of outputting a signal for notification regarding poor reception of the target radio wave when the signal level at the determination frequency is equal to or higher than a predetermined level, or at the determination frequency When a signal level is equal to or higher than a predetermined level, a signal for notifying that the reception state of the target radio wave is bad is output, and when the signal level at the determination frequency is equal to or higher than a predetermined level, the reception sensitivity of the receiving unit The radio wave signal notification device according to claim 1, wherein the radio wave signal notification device is attenuated. When the signal level at the determination frequency is equal to or higher than a predetermined level, the reception sensitivity of the reception unit is set to the attenuated state, and after the predetermined time, the attenuation state of the reception sensitivity of the reception unit is canceled. When the level is less than a predetermined level, the attenuation of the reception sensitivity is canceled. On the other hand, when the signal level at the determination frequency after the cancellation is equal to or higher than the predetermined level, the attenuation state is set again and the target radio wave is set. The radio signal notification apparatus according to claim 3, wherein a signal for notification related to reception is not output.   The program for making a computer implement | achieve the function in the radio signal alerting | reporting apparatus in any one of Claims 1-4.

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