JPH07273744A - Movement speed detection circuit - Google Patents

Abstract

PURPOSE:To detect the movement speed or a receiver without enlarging the device scale by measuring the frequency of branch switching in the receiver which uses a reception signal level measuring instrument of one system to perform diversity reception. CONSTITUTION:In a branch selection control circuit 21, a switch 22 is switched to a branch 1 to measure the reception signal level of the branch 1, and the switch 22 is switched to a branch 2 to measure the reception signal level of the branch 2. Reception signal levels of branches 1 and 2 are compared with each other, and the switch 22 is fixed to the branch, whose measured reception signal level is higher, to receive data of its own slot. A branch switching frequency measuring circuit 23 counts the frequency of branch switching of the switch 22 to measure the frequency of branch switching. In a switching frequency/movement speed conversion circuit 10, the frequency of branch switching is multiplied by a prescribed constant to output the movement speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving speed detecting circuit for a demodulator in mobile communication.

[0002]

2. Description of the Related Art FIG. 21 is a "movement speed estimation method using reception diversity", IEICE Spring National Convention, B.
It is a block diagram which shows the conventional moving speed detection circuit shown by -401 (1993-5). The moving speed detection circuit of FIG. 21 measures the branch switching frequency in a receiver that performs post-detection selective diversity reception that employs demodulated data of the branch with the higher received signal level of the received signals of the two branches. This is a circuit for detecting the moving speed of the receiver. In FIG. 21,
1 is an input terminal of a signal received in a first branch (hereinafter referred to as branch 1), 2 is an input terminal of a signal received in a second branch (hereinafter referred to as branch 2), 3 and 4 are input, respectively First and second reception signal level measuring devices (hereinafter RSSI1, R) which output reception signal levels at terminals 1 and 2
SSI2), 5 and 6 are RSSI1 and RS respectively
First and second A / D converters (hereinafter referred to as A / D1 and A / D2) for A / D converting the SI2 output, and 7 are A / D1 and A
/ D2 output is an input, a level comparator for selecting the branch having the higher received signal level and outputting the branch selection signal to the outside, 8 is an output terminal for outputting the branch selection signal, and 9 is an input for the level comparator output Branch switching frequency measuring circuit for outputting branch switching frequency, 10
Is a switching frequency / moving speed conversion circuit which outputs the moving speed with the output of the branch switching frequency measuring circuit as an input, 11
Is an output terminal for outputting the moving speed.

The operation principle of this conventional example will be described below. The signals received by the two branches are input from the input terminals 1 and 2, respectively, and the RSSIs 3 and 4 output the received signal levels of the respective branches. These RSSI outputs are A
The D / D converters 5 and 6 convert the signals into digital signals, the level comparator 7 compares the magnitudes of the signals, selects the branch having the higher received signal level, and outputs the branch selection signal from the output terminal 8. . By using this branch selection signal, the received data is selected from the demodulated data of each branch, so that selective diversity reception after detection is performed. At the same time, the branch switching frequency measuring circuit 9
The frequency at which the branch selected by the branch selection signal switches is measured. Assuming that the switching frequency is proportional to the moving speed, the switching frequency / moving speed converting circuit 10 converts the moving frequency into the moving speed, and the moving speed is output from the output terminal 11.

Next, the switching frequency / moving speed conversion circuit 1
0 will be described. FIG. 22 shows the moving speed Va of the receiver,
An example of received signal levels of two branches in selective diversity reception after detection when Vb has a two-to-one relationship is shown. In the figure, the arrow on the time axis indicates that the branch selected at that time has been switched. As shown in FIG. 22, the reception signal level drops as the receiver moves, and its frequency is proportional to the moving speed of the receiver. Therefore, from FIG. 22, it is considered that the branch switching frequency is proportional to the moving speed, and the moving speed can be estimated by measuring the branch switching frequency.

[0005]

The conventional moving speed detecting circuit has a problem that the receiving signal level measuring device requires two systems as described above and the device scale becomes large.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a receiver for performing diversity reception using a reception signal level measuring device of one system, without increasing the device scale. Is to detect.

[0007]

In order to solve the above problems, the present invention according to claim 1 is a means for selecting a reception signal from a plurality of branches by a selection signal in a moving speed detection circuit used in a demodulator. A received signal level measuring means for measuring the level of the selected received signal, and the received signal level of each branch immediately before the own slot,
Branch selection control means for outputting the selection signal with the branch having the highest received signal level as the reception branch of its own slot, branch switching frequency measuring means for measuring the branch switching frequency of the branch selection control means, and the branch switching frequency Speed detection circuit composed of a switching frequency / moving speed converting means for converting a moving speed into a moving speed.

In order to solve the above-mentioned problems, the present invention according to claim 2 is a moving speed detection circuit used in a demodulator, and a means for selecting a reception signal from a plurality of branches by a selection signal, and the above-mentioned selection. Received signal level measuring means for measuring the level of the received signal, and branch selection control means for outputting the selected signal of the received branch so as to switch to another branch when the received signal level of its own slot becomes lower than the threshold value. And a moving speed detecting circuit comprising branch switching frequency measuring means for measuring the branch switching frequency of the branch selection control means, and switching frequency / moving speed converting means for converting the branch switching frequency into moving speed.

In order to solve the above-mentioned problems, the present invention according to claim 3 is a moving speed detection circuit used in a demodulator, and a means for selecting a reception signal from a plurality of branches by a selection signal, and the above-mentioned selection. Received signal level measuring means for measuring the level of the received signal, and of the received signal levels of the respective branches immediately before the own slot, the branch having the highest received signal level is used as the received branch of the own slot to output the selection signal, A branch selection control unit that outputs the selection signal of the reception branch so as to switch to another branch when the reception signal level of the slot becomes lower than the threshold, and the branch switching frequency of the branch selection control unit is measured. Branch switching frequency measuring means and converting the branch switching frequency into moving speed Moving speed detection circuit constituted by Toggles frequency / moving speed conversion means.

In order to solve the above-mentioned problems, the present invention according to claim 4 is a moving speed detection circuit used in a demodulator, and a means for selecting a reception signal from a plurality of branches by a selection signal, and the above-mentioned selection. Received signal level measuring means for measuring the level of the received signal, and branch selection for outputting the selection signal with the branch having the highest received signal level among the received signal levels of each branch immediately before the own slot as the receiving branch of the own slot. Control means, in any particular branch, a level variation frequency measuring means for measuring the frequency at which the difference between the selected received signal levels immediately before the previous own slot and immediately before the current own slot becomes larger than a threshold, and the level variation frequency Speed detection circuit composed of a level fluctuation frequency / moving speed converting means for converting to a moving speed.

In order to solve the above-mentioned problems, the present invention according to claim 5 is, in a moving speed detection circuit used in a demodulator, a means for selecting a reception signal from a plurality of branches by a selection signal, and the reception signal. A received signal level measuring means for measuring the level, and a branch selection control means for outputting the selection signal as the receiving branch of the own slot with the branch having the largest received signal level among the received signal levels of each branch immediately before the own slot, , Level fluctuation frequency measuring means for measuring the frequency at which the difference between the received signal levels immediately before and immediately after the own slot of any specific branch exceeds the threshold, and level fluctuation frequency / movement for converting the level fluctuation frequency into a moving speed. A moving speed detection circuit composed of speed converting means.

[0012]

According to the moving speed detecting circuit of the present invention, the reception signal level of a plurality of branches is measured immediately before the own slot, and the antenna selection diversity reception is performed in which the branch having the largest received signal level receives the data of the own slot. In the receiver to be used, the moving speed can be detected by the reception signal level measuring device of one system by measuring the branch switching frequency.

According to another aspect of the present invention, in the moving speed detection circuit, when the data of the own slot is being received and the received signal level of the receiving branch becomes lower than the threshold, the antenna is switched to another branch to receive the data. By measuring the branch switching frequency in the receiver that performs the above, the moving speed can be detected by the reception signal level measuring device of one system.

According to another aspect of the moving speed detecting circuit of the present invention, in a receiver which performs a combination of antenna selection diversity reception and antenna switching diversity reception, a branch signal switching frequency is measured to measure the reception signal level of one system. The moving speed can be detected.

According to another aspect of the present invention, there is provided a mobile speed detection circuit which measures the reception signal level of a plurality of branches immediately before the own slot and performs antenna selection diversity reception in which the branch having the largest reception signal level receives the data of the own slot. In the receiver to perform, by measuring the frequency at which the difference between the received signal level immediately before the current own slot and immediately before the current own slot of any particular branch becomes larger than the threshold, the moving speed is measured by one system of the received signal level measuring device. Can be detected.

In the moving speed detecting circuit according to the present invention, the reception signal level of a plurality of branches is measured immediately before the own slot, and antenna selection diversity reception is performed in which the branch having the largest received signal level receives the data of the own slot. In the receiver to perform, by measuring the frequency at which the difference between the received signal levels immediately before and immediately after the own slot of any specific branch becomes larger than the threshold, it is possible to detect the moving speed with the received signal level measuring device of one system. it can.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1. FIG. 1 shows a block diagram of the configuration of a first embodiment of the moving speed detection circuit of the present invention. The moving speed detection circuit of the present embodiment is a circuit that detects the moving speed of the receiver by measuring the switching frequency of branches in the receiver that performs antenna selective diversity reception. In FIG. 1, the same parts as those in the conventional example are designated by the same reference numerals. In FIG. 1, reference numeral 21 is a branch selection control circuit for selecting which branch receives data of its own slot, 22 is a switch for switching branches based on the selection result of the branch selection control circuit 21, and 23 is selection of the branch selection control circuit 21. A branch switching frequency measuring circuit that measures the branch switching frequency from the result, and 24 is an output terminal that outputs the reception signal of the selected branch to the demodulation unit that demodulates the data. The number of branches is two.

Next, the operation of the first embodiment will be described with reference to FIGS. 2 is an explanatory diagram showing a received signal level measuring method when performing antenna selection diversity reception, FIG. 3 is a flowchart showing the operation of the branch selection control circuit 21, and FIG. 4 is a branch switching frequency measuring circuit 23.
3 is a flowchart showing the operation of FIG.

In the case of 3-channel TDM (time division multiplexing),
As shown in FIG. 2, data of its own slot is received for a time corresponding to ⅓ of one frame, and data received by another receiver is transmitted to slots other than its own slot. In a receiver that performs antenna selection diversity reception,
In the portion of the data to the other receiver immediately before the own slot, the branch to be received is switched by the switch 22 of FIG.
The received signal level is measured by the SSI 3 and the A / D converter 5. In the own slot, the switch 22 is fixed to the branch having the larger measured received signal level, and the received signal of the branch is output from the output terminal 24 to receive the data of the own slot.

In the branch selection control circuit 21, the switch 22 is switched to branch 1 in steps 31 and 32 of FIG. 3 to measure the received signal level of branch 1, and step 3
At 3 and 34, the switch 22 is switched to the branch 2 and the received signal level of the branch 2 is measured. In step 35, the received signal levels of branch 1 and branch 2 measured in steps 31 to 34 are compared. If branch 1 is larger, the switch 22 is switched to branch 1 in step 36. As a result, in step 37, the switch 22 is fixed to the branch having the higher received signal level measured and the data of the own slot is received.

In the branch switching frequency measuring circuit 23,
In step 41 of FIG. 4, the branch selected in the previous own slot and the branch selected in the current own slot are compared. If they are different, the number of branch changes is counted in step 42, and the branch change frequency is measured in step 43. To do.

Switching frequency / moving speed conversion circuit 1 of FIG.
At 0, the moving speed is output by multiplying the branch switching frequency by a constant.

Example 2. FIG. 5 shows a configuration block diagram of a second embodiment of the moving speed detection circuit of the present invention. The moving speed detection circuit of the present embodiment is a circuit that detects the moving speed of the receiver by measuring the branch switching frequency in the receiver that performs antenna switching diversity reception. In FIG. 5, the same parts as those in the conventional example are designated by the same reference numerals. In FIG. 5, reference numeral 51 is a branch selection control circuit that determines whether or not to switch to another branch while receiving data in its own slot, and 53 is a branch switching frequency measurement that measures the branch switching frequency from the selection result of the branch selection control circuit 51. Circuit. The number of branches is two.

Next, the operation of the second embodiment will be described with reference to FIGS. 6 is an explanatory view showing a received signal level measuring method when performing antenna switching diversity reception, FIG. 7 is a flowchart showing an operation of the branch selection control circuit 51, and FIG. 8 is a flowchart showing an operation of the branch switching frequency measuring circuit 53. is there.

In the receiver for performing the antenna switching diversity reception, as shown in FIG. 6, the received signal level of the branch which is currently receiving while receiving the data of its own slot, the RSSI 3 and A / D converter 5 of FIG. Measured with
When the received signal level becomes lower than a predetermined threshold, the switch 22 is switched to another branch, the received signal is output from the output terminal 24, and the data is received.

The branch selection control circuit 51 measures the received signal level of the branch currently being received in step 61 of FIG. 7, and compares the received signal level with the threshold in step 62. If the received signal level is lower than the threshold, the switch 22 is switched to another branch in step 63 to receive the data. In step 64, it is judged whether or not the own slot is ended, and if data of the own slot is being received, steps 61 to 63 are repeated.

In the branch switching frequency measuring circuit 53,
In step 71 of FIG. 8, the number of branch switching is counted by the branch switching signal from the branch selection control circuit 51, and in step 72 the branch switching frequency is measured.

Switching frequency / moving speed conversion circuit 1 of FIG.
At 0, the moving speed is output by multiplying the branch switching frequency by a constant.

Example 3. FIG. 9 is a block diagram showing the configuration of the moving speed detecting circuit according to the third embodiment of the present invention. The moving speed detection circuit of this embodiment is a circuit that detects the moving speed of a receiver by measuring the branch switching frequency in a receiver that combines antenna selection diversity reception and antenna switching diversity reception. In FIG. 9, the same parts as those in the conventional example are designated by the same reference numerals. In FIG. 9, reference numeral 81 is a branch selection control circuit for selecting which branch receives data in its own slot, and determining whether to switch to another branch while receiving data in its own slot, and 82 is a branch selection control circuit. A branch switching frequency measuring circuit for measuring the branch switching frequency from the selection result of 81. Also,
The number of branches is 2.

Next, the operation of the third embodiment will be described with reference to FIGS.
This will be described with reference to 2. 10 is an explanatory diagram showing a received signal level measuring method in the case of performing antenna selection diversity reception and antenna switching diversity reception in combination, FIG. 11 is a flowchart showing the operation of the branch selection control circuit 81, and FIG. 12 is a branch switching frequency measurement circuit. It is a flow chart which shows operation of 82.

In a receiver which performs a combination of antenna selection diversity reception and antenna switching diversity reception, as shown in FIG. 10, a branch received by the switch 22 of FIG. 9 in a portion of data to another receiver immediately before the own slot is received. And the received signal level is measured by the RSSI 3 and the A / D converter 5. In the own slot, the switch 22 is fixed to the branch having the larger measured received signal level, and the received signal of the branch is output from the output terminal 24 to receive the data of the own slot.
Also, while receiving the data of its own slot, the received signal level of the branch currently being received is measured by the RSSI 3 and the A / D converter 5, and when the received signal level becomes lower than a predetermined threshold, the switch is performed. 22 is switched to another branch, a reception signal is output from the output terminal 24, and data is received.

In the branch selection control circuit 81, the switch 22 is switched to the branch 1 to measure the received signal level of the branch 1 in steps 91 and 92 of FIG. 11, and the switch 22 is switched to the branch 2 in steps 93 and 94 to branch the branch 2. Measure the received signal level of 2. In step 95, the received signal levels of branch 1 and branch 2 measured in steps 91 to 94 are compared. If branch 1 is larger, the switch 22 is switched to branch 1 in step 96. As a result, the branch with the larger measured received signal level starts receiving the data of the own slot. In step 97 while receiving the data of its own slot, measure the received signal level of the branch currently being received,
In step 98, the received signal level is compared with the threshold. If the received signal level is lower than the threshold, the switch 22 is switched to another branch in step 99.
To switch to receive data. In step 100, it is judged whether or not the own slot has ended, and if data of the own slot is being received, steps 97 to 99 are repeated.

In the branch switching frequency measuring circuit 82,
In step 111 of FIG. 12, the number of branch switching is counted by the branch switching signal from the branch selection control circuit 81, and in step 112 the branch switching frequency is measured.

Switching frequency / moving speed conversion circuit 1 of FIG.
At 0, the moving speed is output by multiplying the branch switching frequency by a constant.

Example 4. FIG. 13 shows a configuration block diagram of a moving speed detection circuit according to a fourth embodiment of the present invention.
The moving speed detection circuit of the present embodiment is a circuit that detects the moving speed of the receiver by measuring the frequency of fluctuations in the received signal level immediately before the own slot in the receiver that performs antenna selective diversity reception. In FIG. 13, the same parts as those in the conventional example are designated by the same reference numerals. In FIG. 13, reference numeral 121 denotes a branch selection control circuit for selecting which branch receives data in its own slot, and 122 a predetermined difference between the received signal levels immediately before the current own slot and immediately before the current own slot of one branch. Is a level fluctuation frequency measuring circuit for measuring the frequency of increase of the threshold value, and 123 is a level fluctuation frequency / moving speed converting circuit for converting the output of the level fluctuation frequency measuring circuit 122 into a moving speed by multiplying it by a constant. The number of branches is two.

Next, the operation of the fourth embodiment will be described with reference to FIGS.
This will be described with reference to FIG. 14 is an explanatory diagram showing the relationship between the moving speed and the level fluctuation frequency, FIG. 15 is a flowchart showing the operation of the branch selection control circuit 121, and FIG. 16 is a flowchart showing the operation of the level fluctuation frequency measuring circuit 122.

FIG. 14 shows an example of the received signal level when the moving speeds Va and Vb of the receiver have a two-to-one relationship. In the figure, the arrow on the time axis indicates that the fluctuation of the received signal level is larger than a certain threshold. As shown in FIG. 14, the reception signal level drops as the receiver moves, and its frequency is proportional to the moving speed of the receiver. Therefore, it is considered from FIG. 14 that the level change frequency is proportional to the moving speed, and the moving speed can be estimated by measuring the level changing frequency.

In the receiver for antenna selective diversity reception, as shown in FIG. 2, the branch to be received is switched by the switch 22 in FIG. 13 in the portion of the data to the other receiver immediately before the own slot, and the RSSI 3 and A
The received signal level is measured by the / D converter 5. In the own slot, the switch 22 is fixed to the branch having the higher received signal level measured, and the received signal of that branch is output from the output terminal 24 to receive the signal of the own slot.

The branch selection control circuit 121 shown in FIG.
Switch 22 to branch 1 in steps 131 and 132
Is switched to measure the received signal level of the branch 1, and the received signal level is output to the level fluctuation frequency measuring circuit 122. Next, in steps 133 and 134, the switch 22 is switched to the branch 2 and the received signal level of the branch 2 is measured. In step 135, steps 131 to 1
The received signal levels of branch 1 and branch 2 measured in step 34 are compared. If branch 1 is larger, step 1
At 36, the switch 22 is switched to branch 1. As a result, in step 137, the switch 22 is fixed to the branch having the higher received signal level measured and the data of the own slot is received.

In the level fluctuation frequency measuring circuit 122, as shown in FIG.
In step 141 of 6, the difference between the received signal levels immediately before the previous own slot and immediately before the current own slot is compared with the threshold,
If the level difference is larger than the threshold, step 14
The number of level fluctuations is counted in 2, and the level fluctuation frequency is measured in step 143.

In the level fluctuation frequency / moving speed conversion circuit 123 of FIG. 13, the moving speed is output by multiplying the level fluctuation frequency by a constant.

Example 5. FIG. 17 is a block diagram showing the configuration of the moving speed detecting circuit according to the fifth embodiment of the present invention.
The moving speed detection circuit of the present embodiment is a circuit that detects the moving speed of the receiver by measuring the frequency of fluctuations in the received signal level immediately before and after the own slot in the receiver that performs antenna selective diversity reception. In FIG. 17, the same parts as those in the conventional example are designated by the same reference numerals. In FIG. 17, reference numeral 151 denotes a branch selection control circuit for selecting which branch receives data in its own slot, 1
Reference numeral 52 is a level fluctuation frequency measuring circuit for measuring the frequency at which the difference between the received signal levels immediately before and immediately after the own slot of one branch becomes larger than a predetermined threshold. The number of branches is two.

Next, the operation of the fifth embodiment will be described with reference to FIGS.
A description will be given with reference to 0. FIG. 18 is an explanatory diagram showing a received signal level measuring method in the moving speed detecting circuit of the present embodiment, FIG. 19 is a flowchart showing the operation of the branch selection control circuit 151, and FIG. 20 is a level fluctuation frequency measuring circuit 15
It is a flowchart which shows operation | movement of 2.

In the receiver for performing antenna selection diversity reception, as shown in FIG. 2, the branch to be received is switched by the switch 22 in FIG. 17 in the portion of the data to the other receiver immediately before the own slot, and RSSI 3 and A are received. /
The D converter 5 measures the received signal level. In the own slot, the switch 22 is fixed to the branch having the larger measured received signal level, and the received signal of the branch is output from the output terminal 24 to receive the data of the own slot. The moving speed detection circuit of the present embodiment also measures the received signal level immediately after its own slot in one branch as shown in FIG.

The branch selection control circuit 151 shown in FIG.
Switch 161, 162 switches to branch 1 switch 22
Is switched to measure the received signal level of the branch 1, and the received signal level is output to the level fluctuation frequency measuring circuit 152. Next, in steps 163 and 164, the switch 22 is switched to the branch 2 and the received signal level of the branch 2 is measured. In Step 165, Steps 161 to 1
The received signal levels of branch 1 and branch 2 measured in 64 are compared, and if branch 1 is larger, step 16
At 6 the switch 22 is switched to branch 1. As a result, in step 167, the switch 22 is fixed to the branch having the higher received signal level measured and the data of the own slot is received. After receiving the data of its own slot, the switches are switched to branch 1 in steps 168 and 169 to measure the received signal level of branch 1, and the received signal level is measured by the level fluctuation frequency measurement circuit 15
Output to 2.

In the level fluctuation frequency measuring circuit 152, as shown in FIG.
In step 171 of 0, the difference between the received signal levels immediately before and immediately after the own slot is compared with the threshold. If the level difference is larger than the threshold, the number of level fluctuations is counted in step 172, and the level fluctuation frequency is measured in step 173.

In the level fluctuation frequency / moving speed conversion circuit 123 of FIG. 17, the moving speed is output by multiplying the level fluctuation frequency by a constant.

[0049]

As described above, according to the present invention as set forth in claims 1 to 3, it is possible to measure the branch switching frequency in a receiver that performs diversity reception using one system of received signal level measuring devices. Thus, the moving speed can be detected without increasing the device scale.

Further, according to the present invention as set forth in claims 4 and 5, the scale of the apparatus is scaled by measuring the frequency of variation of the received signal level in the receiver which performs diversity reception using one system of the received signal level measuring instrument. The moving speed can be detected without increasing

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing a moving speed detection circuit according to a first embodiment.

FIG. 2 is an explanatory diagram showing a method of measuring a received signal level when performing antenna selective diversity reception.

FIG. 3 is a flowchart showing the operation of the branch selection control circuit shown in FIG.

FIG. 4 is a flowchart showing an operation of the branch switching frequency measuring circuit shown in FIG.

FIG. 5 is a configuration block diagram showing a moving speed detection circuit according to a second embodiment.

FIG. 6 is an explanatory diagram showing a method of measuring a received signal level when performing antenna switching diversity reception.

FIG. 7 is a flowchart showing an operation of the branch selection control circuit shown in FIG.

8 is a flowchart showing the operation of the branch switching frequency measuring circuit shown in FIG.

FIG. 9 is a configuration block diagram showing a moving speed detection circuit according to a third embodiment.

FIG. 10 is an explanatory diagram showing a method of measuring a received signal level in the case of performing antenna selection diversity reception and antenna switching diversity reception in combination.

11 is a flowchart showing the operation of the branch selection control circuit shown in FIG.

FIG. 12 is a flowchart showing the operation of the branch switching frequency measuring circuit shown in FIG.

FIG. 13 is a configuration block diagram showing a moving speed detection circuit according to a fourth embodiment.

FIG. 14 is an explanatory diagram showing a relationship between a moving speed and a level change frequency.

15 is a flowchart showing an operation of the branch selection control circuit shown in FIG.

16 is a flowchart showing the operation of the level fluctuation frequency measurement circuit shown in FIG.

FIG. 17 is a configuration block diagram showing a moving speed detection circuit according to a fifth embodiment.

FIG. 18 is an explanatory diagram showing a method of measuring a received signal level of the moving speed detection circuit according to the fifth embodiment.

19 is a flowchart showing the operation of the branch selection control circuit shown in FIG.

20 is a flowchart showing the operation of the level fluctuation frequency measurement circuit shown in FIG.

FIG. 21 is a configuration block diagram showing a conventional moving speed detection circuit.

FIG. 22 is an explanatory diagram showing a relationship between a moving speed and a branch switching frequency.

[Explanation of symbols]

 1 Branch 1 Input Terminal 2 Branch 2 Input Terminal 3 First Received Signal Level Measuring Device 4 Second Received Signal Level Measuring Device 5 First A / D Converter 6 Second A / D Converter 7 Level Comparator 8 branch selection signal output terminal 9 branch switching frequency measuring circuit 10 switching frequency / moving speed conversion circuit 11 moving speed output terminal 21 branch selection control circuit 22 switch 23 branch switching frequency measuring circuit 24 received signal output terminal 51 branch selection control circuit 53 branch Switching frequency measurement circuit 81 Branch selection control circuit 82 Branch switching frequency measurement circuit 121 Branch selection control circuit 122 Level fluctuation frequency measurement circuit 123 Level fluctuation frequency / moving speed conversion circuit 151 Branch selection control circuit 152 Level fluctuation frequency measurement circuit

Claims (5)

[Claims] 1. A moving speed detection circuit used in a demodulator, comprising means for selecting a reception signal from a plurality of branches by a selection signal, reception signal level measuring means for measuring the level of the selected reception signal, and Of the received signal levels of each branch immediately before the slot, the branch selection control means for outputting the selection signal with the branch having the highest received signal level as the reception branch of the own slot, and the branch switching frequency of the branch selection control means A moving speed detecting circuit comprising: a branch switching frequency measuring means for measuring; and a switching frequency / moving speed converting means for converting the branch switching frequency into a moving speed. 2. A moving speed detection circuit used in a demodulator, which comprises means for selecting a reception signal from a plurality of branches by a selection signal, reception signal level measuring means for measuring the level of the selected reception signal, and A branch selection control unit that outputs the selection signal of the reception branch so as to switch to another branch when the reception signal level of the slot becomes lower than the threshold, and the branch switching frequency of the branch selection control unit is measured. A moving speed detecting circuit comprising branch switching frequency measuring means and switching frequency / moving speed converting means for converting the branch switching frequency into moving speed. 3. A moving speed detection circuit used in a demodulator, which comprises means for selecting a reception signal from a plurality of branches by a selection signal, reception signal level measuring means for measuring the level of the selected reception signal, and Of the received signal level of each branch immediately before the slot, the branch having the highest received signal level is output as the selected signal as the receiving branch of the own slot, and when the received signal level of the own slot becomes smaller than the threshold value. Branch selection control means for outputting the selection signal of the reception branch so as to switch to another branch, branch switching frequency measuring means for measuring the switching frequency of the branch of the branch selection control means, and the branch switching frequency as the moving speed. A switching frequency / moving speed converting means for converting; Moving speed detection circuit. 4. A moving speed detection circuit used in a demodulator, comprising means for selecting a reception signal from a plurality of branches by selection signals, reception signal level measuring means for measuring the level of the selected reception signal, and Of the received signal levels of each branch immediately before the slot, a branch selection control unit that outputs the selection signal with the branch having the highest received signal level as the receiving branch of the own slot, and in any specific branch, immediately before the previous own slot And a level fluctuation frequency measuring means for measuring a frequency at which the difference between the received signal levels immediately before the current slot becomes larger than a threshold, and a level fluctuation frequency / moving speed converting means for converting the level fluctuation frequency into a moving speed. A moving speed detection circuit characterized by. 5. A moving speed detection circuit used in a demodulator, means for selecting a reception signal from a plurality of branches by a selection signal, reception signal level measuring means for measuring the level of the selected reception signal, and Of the received signal levels of each branch immediately before the slot, a branch selection control unit that outputs the selection signal with the branch having the highest received signal level as the received branch of its own slot, and immediately before and immediately after the own slot of any specific branch. And a level fluctuation frequency / moving speed converting means for converting the level fluctuation frequency into a moving speed, and a level fluctuation frequency measuring means for measuring a frequency at which the difference between the received signal levels becomes larger than a threshold. Speed detection circuit.