JPS6052129A - Discriminating circuit of operating mode for mobile radio equipment - Google Patents

Abstract

PURPOSE:To automate discrimination to which operating mode the mode belongs by obtaining a running speed of a mobile body on which a radio equipment is mounted. CONSTITUTION:A comparator circuit 7 compares a reception voltage level from FM receivers 3, 4 connected respectively to antennas 1, 2. Further, a counter circuit 8 counts the number of inverting times in a prescribed time when the relation of both reception voltage levels is inverted as the result of the comparison by the circuit 7. Moreover, an operating mode discriminating circuit 9 discriminates the operating mode from the result of count of the circuit 8. Thus, whether the radio equipment is used while being mounted on a vehicle or used while being carried is discriminated automatically.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to a mobile radio device, and more specifically, the present invention relates to a mobile radio device, and more specifically, a mobile radio device is mounted on a car and operates while moving at high speed. The second mode of operation is when the device is in use mode, or when it is carried by a person and operates at low speed.
This invention relates to a usage mode determination circuit for a radio device that automatically determines whether the radio device is in a usage mode using the received voltage level output of a received wave in the radio device. [Background of the Invention] Land mobile communications in recent years As technology advances, it has become possible to not only make calls using a cordless telephone with a wireless device mounted on a moving object such as a car, but also make the same call with a person carrying a wireless device. . For this reason, it often happens that one radio device is used both as a vehicle-mounted radio device and as a portable radio device.

By the way, in land mobile radio wave propagation, radio waves undergo deep aging at high speed due to multiple wave propagation. The speed of this fading strongly depends on the moving (running) speed of the moving object, and since there is a large difference in moving speed between when the moving object is mounted in a vehicle and when carried by a person, the propagation characteristics of radio waves are significantly different. Therefore, it can be said that the usage mode of the same radio device differs when it is installed in a car and when it is carried. desired.

[Purpose of departure]

The present invention was made against the background of the above-mentioned social needs, and therefore, the purpose of the present invention is to meet the above-mentioned needs of society.
An object of the present invention is to provide a circuit for automatically determining the mode of use in a radio device, which is absolutely necessary for realizing a land mobile communication system that can provide communication services suitable for the mode of use.

[Key points of the invention]

The gist of the present invention is to provide a mobile radio comprising at least two antennas and at least two FM receivers connected to each of the antennas and capable of detecting and outputting the received voltage level of received waves. In the apparatus, a comparison circuit that compares received voltage levels output from each of the FM receivers, and when the magnitude relationship of the re-received voltage levels is reversed as a result of the comparison,
A counting circuit is provided for counting the number of times of reversal within a certain period of time, and the use mode of the wireless device is determined from the counting result.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described with reference to the drawings.

The figure is a block diagram showing one embodiment of the present invention.

In the same figure, 1 and 2 are branches #1 and +, respectively.
2, 3 and 4 are respectively FM receivers belonging to branch l) + 2, 5°6 are reception carrier amplitude (hereinafter referred to as reception voltage level) outputs, each belonging to branch 1.41-2, and 7 is A level comparator s8 for comparing the levels of received voltage level outputs 5 and 6 is a counting circuit, 9 is a usage mode determination circuit, 10 is a usage mode determination output, 11 is a clock input, 12 is a transmitting antenna, 13 is an FM transmitter.

When using a radio device such as the one shown in the figure, installed in a vehicle or carried, a transmitting antenna 12. Using the FM transmitter 13, the receiving antenna 1 or 2, and the FM receiver 6 or 4, it is possible to communicate with the general telephone line network via a radio base station, radio control station, mobile station switching center, etc. (not shown). You can make and receive phone calls.

Next, circuit operation related to the present invention will be explained.

FM fading on receiving antennas 1 and 2
When the modulated wave arrives, FM receivers 3 and 4 demodulate the received wave and send branches: l+1 . #l: Output the received voltage Vpel outputs 5 and 6 belonging to 2, respectively. The level comparator 7 compares the levels of the received voltage level outputs 5 and 6 every clock of the input clock 11, and if the result is the same as the level comparison result made with the clock 1 bit earlier, the level comparator 7 outputs a logic "'0". If the results are different, a logic @'1'' is output. That is, the level comparator 7 detects a state in which the level relationship between the received voltage levels 5 and 6 is inverted.

The counting circuit 8 has a built-in timer and counter, counts the number of times the output of the level comparator 7 becomes logic 61'', and outputs the counting result. If the period is To, then the counting circuit 8 measures the output of the level comparator 7 N times (=TM/To). During this time, the counter of the counting circuit 8 indicates that the output of the level comparator 70 is a logic "'1N". It is assumed that the number of times that becomes is counted once. Then, after the measurement time TM, the rate at which the magnitude relationship of the levels of the received voltage V bell outputs 5 and 6 is reversed (
fc (hereinafter referred to as level crossing rate) can be expressed as equation (1).

f("' tt /N (1) By the way, the frequency afv of the fading pitch in the above-mentioned land mobile radio wave propagation is given by equation (2).

rD-v/λ...-(2) However, ■; Traveling speed λ of the moving object: r is the wavelength of the received wave or the voltage level of the received wave under Lehle fading, and the probability density function of the voltage level r is Let P(r) be P(r), P(r) is given by equation (3).

However, if σ3 is the average value of the rate at which the received wave power level and the received voltage level r cross the set level R with a positive slope, then f(R) is expressed by equation (4). It will be done.

Therefore, if the average rate (level crossing rate) at which the received voltage level output 5 and output 60 magnitude relationship is reversed is fc, then
From equations (2), (3)j and (4), the following equation holds true.

11/λ (5) Therefore, if the level crossing rate fc of the received voltage level is measured using the circuit shown in the figure, the equation (1) is obtained.

From (5), the average traveling speed of the moving object can be calculated.

For example, when a radio is mounted on a car and used, the running speed is usually about 40 km/hr, so if the frequency of the received wave is 800 Mllz, the level crossing rate fc is!
It will be about 10IIZ. Furthermore, when the radio is used in the m band, the traveling speed is about 4 km/hr, so the level crossing rate fc is about 51 Jz.

Therefore, in the usage mode determination circuit 9 in the figure, when the level crossing rate output from the counting circuit 8 is 15 flz or more, the usage mode determination output 10 is set to logic "1", 15-
If you set the output 10 to 5 so that the logic becomes 10'' in the following cases, it will be possible to set the output 10 to 5 when the vehicle is running at about 40 km/hr and 4 km/hr.
It is possible to determine the mode of use in each of the modes of use when the vehicle is carried while traveling at a speed of about 100 hrs.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to determine the running speed of a moving object equipped with a radio device, so that it is possible to determine whether the radio device is being used in a vehicle or being carried. There is an advantage that it is possible to automatically determine whether the device is being used, that is, which usage mode it is in.

In addition, in this embodiment, the usage mode determination criterion is based on one logical value, and the case where two usage modes are distinguished is handled. Of course, it is also possible to do so.

Taking the car telephone system as an example of an application field of the present invention,
Possible application examples include the following.

(b) If the call connection control sequence between the user and the base station is changed based on the judgment result of the in-vehicle/mobile phone judgment circuit, that is, the use mode judgment circuit, an appropriate control method can be adopted depending on the radio wave propagation state. Therefore, it is possible to improve the call connection rate. This example (figure) shows how to use the determination results.
As shown in , the judgment output 10 is returned to the FM transceivers 5, 4, and 15, and the control sequence of the radio itself is changed (the judgment result is also transmitted to the base station by the FM transmitter 13, It is also possible to change the control sequence of the base station.

(b) If the time constant of the symbic compander used in the audio circuit of a car phone is changed based on the judgment result of the usage mode judgment circuit, the audio signal can be compressed or expanded according to the radio wave propagation state. This makes it possible to improve call quality.

The field of application of the present invention includes the above-mentioned 1-day,
Needless to say, the effects of its application are extremely large.

In the embodiment of the present invention, a transmitting antenna and a receiving antenna are separately provided, but one antenna can also be used as both a transmitting antenna and a receiving antenna.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. Code explanation 1.2...Receiving antenna, 6, 4...
・FM reception! , 5, 6... Reception voltage level output, 7... Level comparator, 8... Counting circuit, 9... Usage mode determination circuit, 10. ...
...Usage mode judgment output, 11-...Clock input, 12...Transmission antenna, 13...
・FM transmitter representative patent attorney Akio Namiki patent attorney representative Kiyoshi Matsuzaki

Claims (1)

[Claims] 1) In a mobile radio device comprising at least two antennas and at least two FM receivers connected to each of the antennas and capable of detecting and outputting a received voltage level of a received wave, A comparison circuit that compares received voltage levels output from each of the FM receivers, and a counting circuit that counts the number of times the received voltage levels are reversed within a certain period of time when the magnitude relationship between the received voltage levels is reversed as a result of the comparison. A circuit for determining a usage mode of a mobile radio device, characterized in that the usage mode of the radio device is determined from the counting result.