JP2016096400A - On-vehicle field intensity measurement display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle field intensity measurement display device that measures a reception signal electric field intensity of a plurality of broadcast waves at a predetermined position, while running on a road with mounting, and in which a circuit scale in which an electric field intensity can be measured by cyclically and sequentially switching a channel is reduced in size.SOLUTION: In a reception circuit of a plurality of channels, frequency switching means is arranged to a local oscillation signal inputted to a mixer circuit, and a reception electric field intensity of a broadcast wave is measured by reception channel cycling type sequential switching means that cyclically and sequentially switches a plurality of predetermined reception channels, while switching the channel.SELECTED DRAWING: Figure 1

Description

The present invention relates to an on-vehicle multi-wave electric field strength measuring apparatus that is mounted on a vehicle and measures and displays the electric field strength of a broadcast wave in a road, particularly a tunnel.

Conventionally, as such an electric field strength measuring apparatus, it can be seen in Patent Document 1.
FIG. 3 shows only the electric field intensity measuring device portion of Patent Document 1. Other configurations include GPS and other position measurement means, and display means for displaying the electric field and position in a graph.
Looking only at the field strength measuring device, the broadcast waves of many channels are measured simultaneously while the vehicle is running. For this purpose, the number of processing units equal to the number of channels is provided.
In 3-A of FIG. 3, the broadcast radio wave input from the antenna 301 is divided into an FM wave and an AM wave by the distributor 302. 3-A shows only the FM wave receivers of a plurality of channels.
In order to suppress high frequency noise, FM waves are transmitted (emphasis) by raising the electric field strength on the high frequency side from the low frequency side on the transmission side, and on the contrary, on the receiving side, the electric field strength on the high frequency side is increased from the low frequency range. Lower (de-emphasis). For this reason, filter constants and amplification factors on the high frequency side and low frequency side are separately set and added. The AM wave receiving unit is different from the FM wave and does not take such measures.
Therefore, the output of the high-frequency amplifier 303 that has been de-emphasized at the FM wave receiving unit is input to the mixer 304, which contains a local oscillation signal from the PLL circuit 305. The difference between the local oscillation signal and the frequency of the high-frequency amplifier and the sum component appear at the output of the mixer 304. Only the frequency difference component is selected by the band pass filter 306, and the RSSI (Received Signal Strength Display) circuit 307 is entered in order to see the electric field strength of this signal, and the signal is input to the AD converter and AD converted, The electric field strength is stored in a memory and displayed. In this way, in Patent Document 1, since the electric field intensities of received waves of a large number of channels are fetched at the same time, a plurality of sets of the above processing circuits are held for the number of channels, so that there is a disadvantage that the circuit scale becomes large. . Note that the RSSI circuit 307 is well known, and is disclosed in Patent Document 2 as 3-B or an improvement thereof. Since the intensity of the electric field is detected on a power-of-two scale, the accuracy and the circuit scale are extremely increased.

Japanese Patent No. 5463448 JP2012-9925

An object of the present invention is to provide a circuit that measures the electric field strength by switching channels cyclically and sequentially in an apparatus that measures the received signal electric field strength of a plurality of broadcast waves at a desired position while traveling on the road in a vehicle. It is to provide an in-vehicle multi-wave electric field strength measuring device with a reduced scale.

The in-vehicle multi-wave electric field strength measuring device of the present invention includes a frequency switching means in a local signal means that inputs to a mixer circuit in a multi-channel receiving circuit, and sequentially switches a plurality of predetermined receiving channels cyclically. The reception channel circulation type sequential switching means measures the received electric field strength of the sequential broadcast wave while switching the channel, and displays it on the position.
This will be described in detail below.

The invention according to claim 1 is an in-vehicle multi-wave electric field strength measuring device,
An antenna that receives broadcast waves, a distributor that distributes radio waves received by the antenna, a high-frequency band filter / amplifier that filters and amplifies the high-frequency signal of the distributed broadcast wave, and an output of the high-frequency band filter / amplifier Receiving mixer, local oscillation signal means for inputting a local oscillation signal to the mixer, a band pass filter for receiving an intermediate frequency output that is output as a result of mixing the reception signal and the local oscillation signal by the mixer, and the band pass An electric field strength measuring circuit that receives the output of the filter and measures the electric field strength, an AD converter that AD converts the measured electric field strength, a memory that stores an output value of the AD converter, and a position on the road Position measuring means to be obtained; position electric field intensity display means for displaying the electric field intensity with respect to the position; control means for controlling them; at least the A reception channel setting means for setting the reception channel and reception order of the transmission in the control means; and a measurement position setting means for setting a value relating to the road position to be measured. The local signal means is connected to the control means. A local oscillation signal for cyclically and sequentially switching channels having different frequencies is output based on the set reception channel and reception order of the broadcast wave, and the electric field strength measurement circuit sequentially measures the electric field strength. To do.

The invention according to claim 2 is the in-vehicle multi-wave electric field strength measuring device according to claim 1,
The measurement position setting means can set or select a distance from a predetermined reference point or an index related to the distance from the reference point.

The invention described in claim 3 is the in-vehicle multi-wave electric field strength measuring device according to claim 1 or 2,
The control means uses the position electric field intensity display means to display the electric field intensity for each channel by combining the measurement positions measured by the position measurement means into positions for one channel of the sequential measurement. Features.

Since it is configured as described above, in the in-vehicle multi-wave electric field strength measuring device of the present invention, even for a large number of broadcast channels, a small-scale circuit measurement circuit performs cyclic and sequential measurements on the channels. The received electric field strength can be displayed with respect to the position on the road where the vehicle has traveled.

It is a figure which shows one embodiment of the vehicle-mounted multiwave electric field strength measuring apparatus of this invention. It is a figure which shows the example of the partial circuit which comprises the vehicle-mounted multiwave electric field strength measuring apparatus of this invention. It is a figure which shows the example of the conventional vehicle-mounted multiwave electric field strength measuring apparatus and a received signal strength display circuit.

An in-vehicle multiwave electric field strength measuring device according to the present invention includes an antenna that receives broadcast waves, a distributor that distributes radio waves received by the antennas, a high-frequency band filter / amplifier that filters and amplifies high-frequency signals of the distributed broadcast waves, and , A mixer for receiving the output of the high frequency band filter / amplifier, a local signal means for inputting a local signal to the mixer, and a band for receiving an intermediate frequency output as a result of mixing the received signal and the local signal by the mixer A pass filter, an electric field strength measuring device (such as an RSSI circuit) that receives the output of the band pass filter and measures the electric field strength, an AD converter that AD converts the measured electric field strength, and an output value of the AD converter Memory for storing; position measuring means for obtaining position on road; position electric field intensity display means for displaying electric field intensity with respect to position; and control means for controlling these A reception channel setting means for setting at least the reception channel and reception order of broadcast waves in the control means, and a measurement position setting means for setting a value relating to the road position to be measured, and the local signal means is set in the control means A local oscillation signal for switching channels having different frequencies cyclically and sequentially is output based on the reception channel and reception order of the broadcast waves, and the electric field intensity is measured successively by an electric field intensity measuring device.

FIG. 1 is a diagram showing an embodiment of an in-vehicle multi-wave electric field strength measuring apparatus according to the present invention.
The on-vehicle multi-wave electric field strength measuring apparatus 100 includes an antenna 110 that receives broadcast waves, a distributor 120 that distributes radio waves received by the antenna 110, a high-frequency band filter / amplifier 130 that filters and amplifies the distributed high-frequency signal, and outputs thereof. Receiving mixer 140, further, local oscillator signal means 150 for inputting a local oscillation signal to mixer 140, bandpass filter BPF 160 for receiving an intermediate frequency output that is output as a result of mixing the received signal and the local oscillation signal, and for receiving the output thereof As an example of the electric field strength measuring circuit, an RSSI circuit 170, an AD converter 180 for AD converting the measured electric field strength, a memory 190 for storing the result, a position measuring means 200 for determining the position of the in-vehicle multi-wave electric field strength measuring device 100, Position field strength display means 210 for displaying the field strength with respect to the position, and control means 2 for controlling them 0, a reception channel setting means 222 for setting at least the reception channel and reception order of broadcast waves in the control means 220, and a measurement position setting means 223 for setting a value related to the road position to be measured. Outputs a local oscillation signal for cyclically and sequentially switching channels having different frequencies based on the broadcast wave reception channel and reception order set in the control means 220, and the electric field strength measurement circuit sequentially Measure.
The electric field strength measuring circuit is not limited to the RSSI circuit because it can be used.

Since various radio waves enter the antenna 110, the distributor 120 distributes the FM wave to the FM high-frequency band filter / amplifier 130 and the AM wave to the AM high-frequency band filter / amplifier 130. To do.
FIG. 1 shows a circuit suitable for an FM wave, but this is not particular. In FM modulation, since the frequency is high, signal strength decreases in the high frequency band, and noise increases, so that emphasis / de-emphasis is performed by increasing the high frequency on the transmission side and transmitting on the reception side. Therefore, a filter is often set for each of the low frequency range and the high frequency range. On the other hand, in the AM modulation, since there is no such fear because the frequency is low, the setting of the filter may be one without dividing it into the low band and the high band. Therefore, the high-frequency band filter / amplifier 130 that receives AM waves may be one series of LPF, amplifier, and BPF.

The mixer 140 mixes (multiplies) two input waves to generate an intermediate wave having the sum and difference frequencies. The band pass filter BPF 160 selects an intermediate wave having a difference frequency.
The local oscillation signal unit 150 generates a local oscillation signal to be supplied to the mixer 140, and includes a frequency switching unit 151, which is driven by a circulation type sequential switching unit 221 of the control unit 220 and circulates in a predetermined order. The frequency is switched. Thus, each channel of the broadcast wave is sequentially demodulated, and the electric field strength is measured.

The input of the control means 220 is provided with reception channel setting means 222 for setting the reception channels to be measured, their order, switching / measurement time, and the like.
The position measuring means 200 is a GPS, a self-contained navigation position measuring means or the like, measures the position of the mounted vehicle, and is stored in the memory via the control means 220.
Measurement position setting means 223 is provided at the input of the control means 220, and information relating to positions to be measured such as measurement start position, measurement position, measurement end position, and the like can be set in advance.
Information on the measurement position can be given by a distance from a predetermined reference point or an index related to the distance from the reference point.
The field strength measured for each channel is displayed in the position field strength display means by combining the measurement positions measured by the measurement means into the positions for one channel of the sequential measurement. This is also done for convenience. This is because the position of the car that is running is shifted by the channel switching time interval, but all the channels are aligned to the position of one of the last channels from the first channel of the channel repetition. The position display is not technically strict, but it is also possible to provide a convenient display that is easy to see.
The control unit 220 pursues the set measurement position as necessary, and performs measurement when the corresponding position is reached.

An RSSI circuit 170, which is an example of an electric field strength measuring circuit, is conventionally known and can be used as shown in FIG. Naturally, the operation is well known, but the operation will be briefly described with reference to 3-B in FIG.
A signal to be measured is input to the Vin input. It is checked whether the intensity of the signal input by LAMP11, LAMP12,... Connected in series is large. When the output of each LAMP outputs a difference from the compared comparison value, the output exceeds the comparison value, and the excess is sequentially compared with the next comparison value.
The output value of each LAMP is changed to a DC value by the rectifier COM, and currents I1, I2,... According to the value flow to the electric resistance R11 and output to Vout. In order to ensure the accuracy of the current flowing through the rectifier COM, the rectifier COM is driven by the reference power supply BGR. The electrical resistance R11 is also important for temperature characteristics and linearity with respect to the magnitude of current. In this way, a DC value corresponding to the received signal strength is obtained.

FIG. 2 is a diagram showing an example of a partial circuit constituting the in-vehicle multi-wave electric field strength measuring device of the present invention.
In FIG. 1, the high-frequency band filter / amplifier 130 is not particularly divided for each channel. Although this can be used sufficiently, in 2-A, a high-frequency band filter / amplifier 130 corresponding to the channel is prepared in order to switch the optimally designed filter corresponding to each channel in response to the channel switching. It is. In 2-B, the high-frequency band filter / amplifier 130 is one set, but the filter coefficient is switched by inputting a control signal from the control means 220 from the C terminal.

In 2-D, a plurality of local oscillation signal transmission means (for example, crystal oscillators) are provided in the local oscillation signal means 150, and this is switched by a control signal from the control means 220. In 2-C, there is one set of means for generating a local oscillation signal, but the oscillation circuit constant that determines the frequency is switched.

Of the high-frequency band filter / amplifier 130, the mixer 140, the local oscillation signal means 150, the band-pass filter 160, and the electric field strength measuring device (RSSI circuit or the like), desired ones can be integrated.

Due to the above configuration, the in-vehicle multi-wave electric field strength measuring device uses a large number of received waves such as at least one electric field strength measuring device by cyclically switching the receiving frequency channel in a predetermined order. Since the measurement system is small and the electric field strength can be displayed corresponding to the position on the road, the industrial applicability is extremely high.

DESCRIPTION OF SYMBOLS 100 Vehicle-mounted multiwave electric field strength measuring apparatus 110, 301 Antenna 120, 302 Divider 130, 303 High frequency band filter / amplifier 140, 304 Mixer 150 Local signal means 151 Frequency switching means 160, 306 Band pass filter BPF
170, 307 Electric field strength measuring device (RSSI circuit, etc.)
180 AD converter 190 Memory 200 Position measurement means 210 Position electric field strength display means 220 Control means 221 Reception channel circulation type sequential switching means 222 Reception channel setting means 223 Measurement position setting means 305 PLL circuit

Claims (3)

An antenna that receives broadcast waves, a distributor that distributes radio waves received by the antenna, a high-frequency band filter / amplifier that filters and amplifies the high-frequency signal of the distributed broadcast wave, and an output of the high-frequency band filter / amplifier Receiving mixer, local oscillation signal means for inputting a local oscillation signal to the mixer, a band pass filter for receiving an intermediate frequency output that is output as a result of mixing the reception signal and the local oscillation signal by the mixer, and the band pass An electric field strength measuring circuit that receives the output of the filter and measures the electric field strength, an AD converter that AD converts the measured electric field strength, a memory that stores an output value of the AD converter, and a position on the road Position measuring means to be obtained, position electric field intensity display means for displaying the electric field intensity with respect to the position, control means for controlling these, and at least the above-mentioned A reception channel setting means for setting the reception channel and reception order of the transmission in the control means; and a measurement position setting means for setting a value relating to the road position to be measured. The local signal means is connected to the control means. A local oscillation signal for cyclically and sequentially switching channels having different frequencies is output based on the set reception channel and reception order of the broadcast wave, and the electric field strength measurement circuit sequentially measures the electric field strength. In-vehicle multi-wave electric field strength measuring device. The in-vehicle multi-wave electric field strength measuring apparatus according to claim 1, wherein the measurement position setting means can set or select a distance from a predetermined reference point or an index related to the distance from the reference point. The control means uses the position electric field intensity display means to display the electric field intensity for each channel by combining the measurement positions measured by the position measurement means into positions for one channel of the sequential measurement. The on-vehicle multi-wave electric field strength measuring device according to claim 1 or 2, characterized in that

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