JP2861635B2 - Wireless receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a road-to-vehicle information communication system for obtaining road information such as vehicle running, and receives a radio wave from a radio transmitter installed on a road in a vehicle. Related to the device.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a radio receiver in a conventional road-vehicle information communication system.

In FIG. 3, reference numeral 1 denotes a receiving antenna for receiving a radio wave (beacon) from a radio transmitter installed on the road, 2 a high frequency amplifier circuit, 3 a frequency mixing circuit, 4 an intermediate frequency amplifier circuit, and 5 a A local oscillation circuit 6 is a data detection circuit for detecting road information. Reference numeral 7 denotes a 1 KHZ detection circuit for detecting an installation position of a wireless transmission device on a road, that is, a distance from the device, 8 denotes an electric field intensity level detection unit, and 10 denotes a signal processing circuit. In the electric field strength level detecting section 8, 9 is a comparator, 11 is a switching transistor, and 12 is a variable resistor.

The intermediate frequency amplification circuit 4 is provided with an envelope detector and the like, and outputs a DC voltage corresponding to the electric field intensity level from an output terminal a from the envelope detector.

[0005] The electric field intensity level detector 8 takes in data in the signal processing circuit 10 and detects the electric field intensity level when transmitting the data as a display signal to a display unit (not shown). Comparator 9 sets an electric field strength level for taking in data. The switching transistor 11 is set to H (high) at the electric field intensity level determined by the comparator 9.
/ L (low) level, and the output is switched to ON / OFF (switching, conduction / non-conduction).
The display signal is transmitted or stopped.

Next, the operation of this conventional example will be described. The radio wave received by the receiving antenna 1 is converted into an intermediate frequency signal through the high frequency amplification circuit 2 and the frequency mixing circuit 3, and a DC voltage corresponding to the electric field intensity level is output to the output terminal a of the intermediate frequency amplification circuit 4.

FIG. 4 (a) shows the DC voltage, the vertical axis represents the DC voltage value corresponding to the electric field strength level, and the horizontal axis represents the position of the radio transmitting apparatus installed on the road as 0 (zero). , The distance from the wireless transmission device.

The comparison reference voltage of the comparator 9 is applied by the variable resistor 12 to, for example, a field strength level of -62 dBm.
Is set, the comparator 9 switches at the set level -62 dBm. The switching transistor 11 is turned on / off by the output H (high) / L (low) level signal.

FIG. 4B shows the on / off state of the output of the switching transistor 11. FIG.
In (b), the vertical axis represents the on / off voltage, and the horizontal axis represents the distance from the wireless transmission device installed on the road. The switching transistor 11 outputs H (high) / L (low) of the output of the comparator 9 at the boundary of the electric field strength level of −62 dBm.
On / off is repeated in accordance with the level signal, and in the case of this on, the signal processing circuit 10 operates to stop the transmission of the display signal in order to avoid frequent display interruptions in a display device (not shown).

In this way, the display signal is sent from the signal processing circuit 10 only at the stable displayable electric field intensity level.

[0011]

In the above-mentioned conventional radio receiving apparatus, when the switching transistor 11 is turned on, the signal processing circuit 10 does not take in the detection data from the data detection circuit 6 and the data processing is interrupted. I will. In other words, there is a problem that the display signal is frequently interrupted in accordance with the electric field intensity level of the radio wave input in the multipath accompanying the traveling of the vehicle, making it difficult to view the display image.

The present invention solves the above-mentioned problem, and frequently interrupts a display signal when demodulating and displaying transmission data from a roadside radio transmitter or the like even if the electric field strength level changes frequently. It is an object of the present invention to provide an excellent wireless receiving apparatus capable of reducing the number of images and making it difficult to view a data display image.

[0013]

In order to achieve the above object, according to the present invention, an electric field intensity voltage corresponding to the electric field intensity level of a received radio wave is output from an output signal of a radio receiving means. and the electric field strength level voltage generating means, said data detecting means for receiving radio waves from the data detection, the detected together with the signal processing for display against the data, a display signal processed by the input of the transmission stop signal Signal processing means for stopping transmission of the signal, and electric field intensity level comparing means for outputting a first signal or a second signal at different levels when the electric field intensity voltage is higher and lower than a preset value, When the electric field intensity voltage is higher than a preset value, the voltage of the first signal output from the electric field intensity level comparing means is changed to a voltage of an electric field intensity level lower than the set value. As a feed stop signal intervals longer than the cutoff time of the field intensity voltage for a configuration and a signal supply means for supplying to said signal processing means.

The electric field intensity level comparing means is a comparator, and the signal supply means receives the first signal from the comparator, and sets the electric field intensity level to the above-mentioned first signal with a discharge time based on a time constant. when longer than the cutoff time of the field intensity voltage for lower than the value
A constant number circuit, and a switching means for supplying the transmission stop signal to the signal processing means is controlled by the voltage from the time constant circuit.

[0015] In the wireless receiving apparatus according to the third aspect,
The configuration is configured to receive a transmission radio wave from a wireless transmission device for transmitting traffic information and transmit a display signal for displaying the traffic information.

[0016]

With such a configuration, the radio receiving apparatus of the present invention converts the low-level signal or the high-level signal voltage when the electric field intensity voltage corresponding to the electric field intensity level of the received radio wave is higher than a preset value. The transmission stop signal set at an interval longer than the cutoff time of the electric field strength voltage when the level falls below the set value is supplied to the signal processing means to stop the transmission of the display signal.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a radio receiving apparatus according to the present invention.

FIG. 1 shows the configuration of the embodiment. In FIG. 1, 11 is a receiving antenna, 12 is a high-frequency amplifier circuit,
13 is a frequency mixing circuit, 14 is an intermediate frequency amplifier circuit (corresponding to the electric field intensity level voltage generating means in the claims),
Reference numeral 15 denotes a local oscillation circuit. 16 is a data detection circuit, 17 is the installation position of the wireless transmission device on the road, ie,
A 1 KHZ detection circuit for detecting the distance from the device, 18 is an electric field intensity level detecting section (corresponding to electric field intensity level comparing means and electric field intensity level detecting means in the claims), and 20 is a signal processing circuit. In the electric field intensity level detector 18, reference numeral 25 denotes a comparator for determining the electric field intensity level for taking in data, 26 denotes an electric field intensity level determined by the comparator 25, and the output is switched to H (high) / L (low). A switching transistor 27 that is turned on / off by the H (high) / L (low) signal is a variable resistor. Reference numeral 29 denotes a time constant circuit in which the discharge time determined by the time constant is set to be longer than the cutoff time based on the electric field intensity level, and includes a diode D1 and a resistor R1.
Are connected in parallel, further grounded by a capacitor C1, and connected in series to the base of the switching transistor 26 by a resistor R2.

The intermediate frequency amplifying circuit 14 outputs a DC voltage corresponding to an electric field intensity level from an envelope detector or the like from an output terminal a.

The electric field intensity level detecting section 18 detects the electric field intensity level when the signal processing circuit 20 fetches data and sends the data as a display signal to a display section (not shown). In the comparator 25, an electric field strength level for taking in data is set, and H (high) is set based on the set value.
/ L (low) level output signal is transmitted. The switching transistor 26 is turned on / off in response to an H (high) / L (low) level output signal from the comparator 25. When the switching transistor 26 is on, the signal processing circuit 20 stops sending a display signal to a display device (not shown). Works.

Next, the operation of this embodiment will be described. The radio wave received by the receiving antenna 1 is converted into an intermediate frequency signal through the high frequency amplifier circuit 12 and the frequency mixing circuit 13, and a DC voltage corresponding to the electric field intensity level is output to the output terminal a of the intermediate frequency amplifier circuit 14.

FIG. 2A shows this DC voltage, the vertical axis represents the DC voltage according to the electric field strength level, and the horizontal axis represents the position of the radio transmitting apparatus installed on the road as 0 (zero). The distance from the wireless transmission device is shown.

In the comparator 25, the comparison reference voltage is changed by the variable resistor 27 to, for example, a field strength level of -62.
The voltage is set to a voltage corresponding to dBm.

The comparator 25 determines that the electric field strength level is-
When the electric field strength level is higher than -62 dBm at the boundary of 62 dBm, an H (high) level output signal is output. When the electric field strength level is lower than -62 dBm, an L (low) level output signal is output.

The switching transistor 26 is turned on / off by an H (high) / L (low) level output signal from the comparator 25. That is, it is turned on at an electric field intensity level of -62 dBm or more, and turned off at an electric field intensity level of -62 dBm or less.

FIG. 2B shows the ON / OFF state of the switching transistor 26. In this case, the time constant circuit 2 in the electric field strength level detector 18 inserted between the comparator 25 and the switching transistor 26
9, the input voltage to the comparator 25 is
7 becomes higher than the voltage set by the time constant circuit 29.
Capacitor C1 is instantaneously charged through the diode D1. Even if the voltage input to the comparator 25, that is, the electric field strength level instantaneously drops below -62 dBm, the previously charged voltage is discharged through the resistors R1 and R2 for a time longer than the drop time of the electric field strength level. .

For this reason, as previously described with reference to FIGS. 3A and 3B, the switching transistor 11 is frequently turned on and off at an electric field strength level of -62 dBm or more, whereas in the embodiment, it is -62 dBm or more. In addition, the ON state of the switching transistor 26 is stably continued by the time constant of the time constant circuit 29. In the ON state of the switching transistor 26 in this stable section, the signal processing circuit 20 does not take in the detection data from the data detection circuit 16. As a result, instantaneous interruption of data processing in the signal processing circuit 20 is eliminated, and display on a display device (not shown) to which a display signal is supplied is difficult to see, and data reception from a wireless transmission device on the road is stabilized. Will be possible.

[0028]

As is apparent from the above description, the radio receiving apparatus according to the present invention provides a low level signal or a high level signal when the electric field intensity voltage corresponding to the electric field intensity level of the received radio wave is higher than a preset value. Since the signal voltage is supplied to the signal processing means with a transmission stop signal set at an interval longer than the cutoff time of the electric field intensity voltage when the electric field intensity level falls below the set value, the transmission of the display signal is stopped. field intensity level is changed frequently also reduce frequent interruption of the display signals for displaying demodulates the transmission data from such road radio transmitting apparatus, an effect of reducing the Midzura of the data display image Have.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a wireless reception device according to the present invention.

FIG. 2A is an explanatory diagram illustrating a waveform of a DC voltage output from an intermediate frequency amplifying circuit in an embodiment, and FIG. 2B is an explanatory diagram illustrating an on / off state of a switching transistor in the embodiment.

FIG. 3 is a block diagram showing a configuration of a conventional radio receiving apparatus.

4A is an explanatory diagram showing a waveform of a DC voltage output from an intermediate frequency amplifier circuit in a conventional example, and FIG. 4B is an explanatory diagram showing an on / off state of a switching transistor in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 High frequency amplifier circuit 13 Frequency mixing circuit 14 Intermediate frequency amplifier circuit 16 Data detection circuit 17 1KHZ detection circuit 18 Electric field intensity level detection unit 20 Signal processing circuit 25 Comparator 26 Switching transistor 27 Variable resistor 29 Time constant circuit

Claims (3)

(57) [Claims] 1. An electric field intensity level voltage generating means for outputting an electric field intensity voltage corresponding to an electric field intensity level of a received radio wave from an output signal of a radio receiving means, a data detecting means for detecting data from the received electric wave, Data
A signal processing means for stopping the transmission of the display signal processed by the input of the transmission stop signal, together with the signal processing for performing the display , and when the electric field intensity voltage is higher and lower than a preset value, respectively. Different levels first
And a first signal output from the electric field intensity level comparing means when the electric field intensity voltage is higher than a preset value.
A signal supply unit for supplying the signal processing unit with the signal processing unit as a transmission stop signal having an interval longer than a cutoff time of the electric field intensity voltage when the electric field intensity level falls below the set value to the signal processing unit. 2. The electric field intensity level comparing means is a comparator, and the signal supply means receives a first signal from the comparator, and sets the electric field intensity level to the above-mentioned first signal with a discharge time based on a time constant. composed of a switching means for supplying a time constant circuit, the transmission stop signal to the signal processing means is controlled by the voltage from the time constant circuit is set longer than the cutoff time of the field intensity voltage for lower than the value The wireless receiving device according to claim 1, wherein: 3. The wireless communication apparatus according to claim 1, wherein a transmission radio wave from a wireless transmission device for transmitting traffic information is received, and a display signal for displaying said traffic information is transmitted.
The wireless receiving device according to claim 1.