JPH10303793A - Diversity receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a demodulation error by adding information of an antenna reception state to an automatic optimum reception frequency selection function, in the case of three or more antenna systems used for a receiver side to conduct diversity reception in a system where same information is sent with plural frequencies through an HF line. SOLUTION: This receiver is provided with a reception system changeover circuit 11, that selects the connection between the antenna system and frequency changeover circuits 1, 2, 3. An optimum frequency selection circuit 12 uses antenna systems 1-3 and operating frequencies f1 -fn to give a switching instruction sequentially for each prescribed time to the reception system changeover circuit 11 and a frequency-changeover circuit 3 and receives and stores the information from a reception state detection circuit 6. When detected information from each of reception state detection circuits 4, 5, 6 indicates not more than a specified level, changeover to a frequency considered to provided a best signal state among those stored in frequency changeover circuits 1, 2 of the reception system is instructed and connection is instructed to any of the higher ranking two system antennas to the reception system changeover circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing diversity reception using three or more antennas on the receiving side in a system for transmitting the same information using a plurality of frequencies on an HF line, The present invention relates to an improvement of a circuit for automatically selecting an optimum frequency when the state of a received signal is deteriorated.

[0002]

2. Description of the Related Art The HF line changes every moment depending on the state of the ionosphere. Therefore, the optimum receiving frequency (the frequency with the least influence of fading and multipath and the least error) varies depending on the season, time, reception distance (distance from the transmission point to the reception point), and the like. If the reception frequency is not changed, reception cannot be performed. For this reason, the diversity receiving apparatus is provided with an automatic optimum receiving frequency selecting circuit.

A conventional optimum reception frequency selection circuit for performing diversity reception of radio waves in the HF band on the receiving side using three or more antennas is configured as shown in FIG.

FIG. 2 shows an example of an optimum receiving frequency selection circuit in a case where selection diversity is performed using three antennas.

In the conventional optimum receiving frequency selecting circuit, when three antennas are present, one of the three antennas is fixed as a receiving state confirmation receiving system (in the configuration example of FIG. This is a dedicated reception system for checking the reception status of the frequency.) The frequency switching circuits 1, 2, 3 are provided with an optimum frequency selection circuit 10
The frequency is switched according to the instruction from. The reception state detection circuits 4, 5, and 6 detect information (S / N information, bit synchronization shift, phase angle shift, etc.) that can be identified and detected as a received signal state for each modulation scheme, and a diversity circuit 9 and an optimal frequency selection. Output to the circuit 10. Demodulation circuits 7 and 8 demodulate the modulated signal and output demodulated data to diversity circuit 9. Diversity circuit 9 performs selection diversity based on the reception state detection information from reception state detection circuits 4 and 5 among the data output from demodulation circuits 7 and 8, and outputs demodulated data.

The optimum frequency selection circuit 10 performs the following operation.

(1) When the power is turned on, an instruction is given to the frequency switching circuit 3 dedicated to checking the reception state in order (f ₁ → f ₂ → f ₃ ... Fn) at regular intervals at the operating frequencies f _{1 to} fn. The reception state detection information from the reception state detection circuit 6 for each frequency is input, and the detection information for the frequency is stored. Then, an instruction is issued to switch the frequency switching circuits 1 and 2 of the other reception systems to the frequency at which the signal state is considered to be the best among the stored detection information.

(2) After the operation of the above-mentioned (1) step is completed, the frequency switching circuit 3 is continuously used for the frequencies f ₁ to f ₁ .
fn (f ₁ → f ₂ → f ₃ ... fn
→ f ₁ → f ₂ → f ₃ → ... is repeated. ), A reception instruction from the reception state detection circuit 6 for each frequency is input, and the detection information for the frequency is stored, and the frequency switching circuits 1 and 2 output the frequency having the best signal state. To switch to.

(3) Reception state detecting circuit 4 for the frequency of the receiving system currently receiving by antennas 1 and 2
When the reception state detection information from the reception state detection circuit 6 and the reception state detection information from the reception state detection circuit 6 is not more than the predetermined value, the optimum frequency selection circuit 10
For the frequency switching circuit 1 or 2 of the receiving system corresponding to the one where the detection information from the reception state detection circuit 4 or 5 is worse, the frequency whose signal state is considered to be the best among the stored reception state detection information. To switch to. Further, before issuing the switching instruction, the diversity circuit 9 is instructed to output only the demodulated data of the system that does not execute the frequency switching as the diversity output.

(4) The frequency is changed in the step (3), and after a predetermined time, an instruction is issued to the frequency switching circuits of other receiving systems to switch to the same frequency. Also, before issuing the switching instruction, the diversity circuit 9 is instructed to output only the demodulation of the system for which the frequency switching has already been performed in step (3) as the diversity output.

(5) The frequency is changed in the above step (4), and after a certain period of time, an instruction is issued to the diversity circuit 9 to execute the normal selection diversity.

[0012]

In the above-mentioned optimum reception selection circuit, the optimum reception frequency selection in consideration of the antenna reception state is not performed, and the antenna 3 system (the reception system dedicated to the reception state confirmation of each frequency) is used. Even when the antenna condition was the best, it could not be used for actual demodulation because the receiving system was fixed, and three antennas could not be used effectively.

[0013] An object of the present invention is to provide a system for transmitting the same information using a plurality of frequencies on an HF line, and performing diversity reception using three or more antennas on the receiving side. By adding the optimal reception system selection function that takes into account the antenna reception state to the selection function,
This is to reduce demodulation errors.

[0014]

The object of the present invention is to provide a plurality of frequency switching circuits for switching the frequency of a received signal of each antenna system, and a receiving system switching circuit for switching the connection between each antenna system and each of the frequency switching circuits. A reception state detection circuit that detects information that can be identified and detected as a reception signal state from a reception signal of each of the frequency switching circuits, a demodulation circuit that demodulates the reception signal of the frequency switching circuit, and demodulation data of each of the demodulation circuits. A diversity circuit for performing selection diversity based on the signal state detection information from the reception state detection circuit, and receiving reception state detection information from each of the reception state detection circuits; From the reception state detection information stored in the frequency switching circuit, a command is issued to switch to a frequency that is considered to have the best signal state, and the reception system switching circuit Instruct the connection to at least one of the upper two antennas whose signal state is considered to be good, and instruct the diversity circuit to output only the demodulated data of the receiving system that does not execute frequency switching when the frequency is switched. This is achieved by providing an optimum frequency selection circuit.

The object of the present invention is to provide the above-mentioned optimal frequency selection circuit, in which the receiving system switching circuit and one frequency switching circuit for confirming the reception state are sequentially switched at predetermined time intervals by the used antenna system and the used frequency. An instruction is issued, the reception state detection information from the reception state detection circuit corresponding to the above-mentioned frequency switching circuit for each antenna system and each frequency is taken in and stored, and from those, the one having the best signal state is selected and the reception is performed. This is achieved by providing a circuit for issuing a switching instruction to the system switching circuit and the frequency switching circuit.

According to the above-mentioned means, the optimum frequency selection circuit instructs the reception system switching circuit and one frequency switching circuit for confirming the reception state to sequentially perform switching at predetermined time intervals based on the used antenna system and the used frequency. And receiving the reception state detection information for each antenna system and frequency, it is possible to always obtain reception state detection information that takes into account the antenna reception state. Then, from the obtained information, the one with the best signal condition is selected and the switching instruction is given to the receiving system switching circuit and the frequency switching circuit. Can be.

The optimum frequency selection circuit, when instructing the receiving system switching circuit and the frequency switching circuit to perform switching, issues an instruction to output only demodulated data of a system that does not perform frequency switching to the diversity circuit at the time of switching. There is no error when switching. After the switching, an instruction is issued to execute normal selection diversity.

[0018]

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

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention.
The point is that a reception system switching circuit 11 is provided between the antenna 3 system and the frequency switching circuits 1, 2, 3.

The receiving system switching circuit 11 switches the connection between each antenna system and the frequency switching circuits 1, 2, 3 according to an instruction from the optimum frequency selecting circuit 12. The receiving system of the frequency switching circuit 3 and the receiving state detecting circuit 6 is used for checking the receiving state.

The frequency switching circuits 1, 2, 3 switch the frequency in accordance with an instruction from the optimum frequency selection circuit 12.

Reception state detection circuits 4, 5, and 6 detect information (S / N information, bit synchronization shift, phase angle shift, etc.) that can be identified and detected as a received signal state for each modulation scheme, and diversify it. The signal is output to the circuit 9 and the optimum frequency selection circuit 12.

The demodulation circuits 7 and 8 demodulate the modulated signal and output demodulated data to the diversity circuit 9.

The diversity circuit 9 performs selection diversity based on the demodulated data output from the demodulation circuits 7 and 8 and the signal state detection information from the reception state detection circuits 4 and 5, and outputs the result as demodulated data.

The optimum frequency selection circuit 12 issues a switching command to each circuit based on the reception state detection information of each of the reception state detection circuits 4, 5, and 6, and performs the following operation.

(1) When the power is turned on, the receiving system switching circuit 11
To the antenna 1 system and the frequency switching circuit 3. Further issues an instruction for switching the frequency f ₁ to the frequency switching circuit 3.

(2) In the same manner as in the above (1) step, the antennas 1 to 3 used and the used frequencies f1 to fn are sequentially arranged at regular intervals (antenna 1 system f ₁ → antenna 2 system f ₁ → antenna 3 system). f ₁ → antenna 1 system f ₂ → antenna 2 system f ₂ → antenna 3 system f ₂ ... antenna 1 system fn → antenna 2 system f
A switching instruction is issued to (n → antenna 3 system fn), and the reception state detection information for each antenna system and frequency at that time is taken in from the reception state detection circuit 6 for confirming the reception state and stored. An instruction is issued to switch the frequency switching circuits 1 and 2 to a frequency that seems to have the best signal state among the stored detection information. Is instructed to connect to the frequency switching circuits 1 and 2 respectively.

(3) After the operation of the above (2) step is completed, the receiving system switching circuit 11 and the frequency switching circuit 3
For the antenna systems 1 to 3 and the use frequencies f _{1 to} fn at regular intervals (antenna 1 system f ₁ → antenna 2 system f _1).
→ antenna 3 system f ₁ → antenna 1 system f ₂ → antenna 2 system f
₂ → Antenna 3 system f ₂ ...... Antenna 1 system fn → Antenna 2
.. (Repeating system fn → antenna 3 system fn → antenna 1 system f ₁ ...), And fetches and stores reception state detection information from the reception state detection circuit 6 for each antenna system and frequency.

(4) The reception state detection information from the reception state detection circuit 6 for the frequency instructed to the frequency switching circuit is equal to or less than a specified value (a systematic reception error is small and an acceptable level value). In the case, or when the reception state detection information from the reception state detection circuits 4 and 5 is equal to or less than the specified value, the optimum frequency selection circuit 12 determines the frequency corresponding to the one where the detection information from the reception state detection circuits 4 and 5 is worse. The switching circuit 1 or 2 is instructed to switch from the stored reception state detection information to a frequency that is considered to have the best signal state. If the antenna system connected by the current receiving system switching circuit 11 is included in the upper two systems in the signal state stored at that frequency, the upper two systems remain as they are. If not, it instructs the reception system switching circuit 11 to connect to an antenna different from the antenna to which the reception system that does not perform frequency switching is connected among the upper two systems. Before issuing the switching instruction, the diversity circuit 9 is instructed to output only the demodulation of the system that does not execute the frequency switching as the diversity output.

(5) After changing the frequency and antenna in the above (4) step, after a certain period of time, the frequency switching circuit and the receiving system switching circuit for other receiving systems below the specified value are also used. Similarly, an instruction is issued to switch to the upper two-system antenna whose frequency and signal condition are considered to be good.
Also, before issuing the switching instruction, the diversity circuit 9
(4) An instruction is issued to output only the demodulation of the system for which the frequency has been switched in the step as the diversity output.

(6) After changing the frequency and antenna in the above (5) step, an instruction is issued to the diversity circuit 9 after a certain period of time to execute normal selection diversity.

[0032]

As described above, according to the present invention, HF
In a system that transmits the same information using multiple frequencies on a line, if diversity reception is performed using three or more antennas on the receiving side, the antenna reception state is added to the automatic optimal reception frequency selection function. By adding the optimum receiving system selection function, demodulation errors can be reduced, and the receiving system (including the antenna) can be used effectively.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention.

FIG. 2 is a conventional circuit configuration diagram.

[Explanation of symbols]

1, 2, 3 ... frequency switching circuit, 4, 5, 6 ... reception state detection circuit, 7, 8 ... demodulation circuit, 9 ... diversity circuit, 1
1 ... Reception system switching circuit, 12 ... Optimal frequency selection circuit.

Claims (3)

[Claims] An apparatus for performing diversity reception of a signal transmitted in the HF band using the same information using a plurality of frequencies using antennas of three or more reception systems, wherein a plurality of signals for switching the frequency of the reception signal of each of the antenna systems are provided. Frequency switching circuit, a reception system switching circuit for switching the connection between each of the antennas and each of the frequency switching circuits, and a reception state detection for detecting information that can be detected and detected as a reception signal state from a reception signal of each of the frequency switching circuits. A demodulation circuit that demodulates a reception signal of the frequency switching circuit; a diversity circuit that performs selection diversity based on demodulation data of each demodulation circuit and reception state detection information from the reception state detection circuit; If the reception state detection information from the circuit is fetched and is less than the specified value, it is stored in the frequency switching circuit of the reception system below the specified value. Of the reception condition detection information, the switching to the frequency having the best signal condition is instructed, and the receiving system switching circuit is connected to at least one of the upper two antennas having the good signal condition. A diversity receiving circuit for instructing the diversity circuit to output only the demodulated data of the receiving system that does not perform frequency switching at the time of the frequency switching. 2. The optimum frequency selection circuit issues an instruction for switching to the receiving system switching circuit and one frequency switching circuit for confirming the reception state in order at predetermined time intervals based on a used antenna system and a used frequency. Receives and stores reception state detection information from a reception state detection circuit corresponding to the above-mentioned frequency switching circuit for each antenna system and frequency, and selects and selects a signal having the best signal state from among the reception system detection circuits. 2. The diversity receiving apparatus according to claim 1, wherein the switching instruction is issued to a frequency switching circuit. 3. The above-mentioned optimum frequency selection circuit fetches reception state detection information from one reception state detection circuit for confirming the reception state and the reception state detection circuit of another reception system. The reception system instructs to switch to a frequency that seems to have the best signal state from among the reception state detection information stored in the frequency switching circuit corresponding to the reception state detection information that is worse among the reception systems having values less than or equal to the value. Instruct the switching circuit to connect to an antenna different from the antenna to which the receiving system that does not perform frequency switching among at least the upper two antennas in which the signal state is considered to be good, and after a certain period of time, a value equal to or less than the specified value 2. The diver according to claim 1, wherein the frequency switching circuit and the receiving system switching circuit corresponding to the other receiving systems are similarly instructed to switch the frequency and connect the antenna. Siti receiver.