JP3443287B2 - Diversity receiver - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity receiver used in, for example, a vehicle-mounted television receiver, and particularly, selects the best antenna for each channel and determines the reception status of the best antenna. If it is a station, it relates to a diversity receiver that stops the seek operation.

[0002]

2. Description of the Related Art For example, an on-vehicle television receiver is provided with a plurality of antennas (for example, four antennas are provided) because it is used in a place where radio wave conditions are present such as a weak electric field area and a strong electric field area. ), The diversity receiver that automatically selects the antenna with the highest input level is adopted.

FIG. 4 shows the operation of the system microcomputer provided in the diversity receiver.
If there is a seek instruction for obtaining a good channel (step 401), the PLL corresponding to the frequency of each channel
At the same time as setting the data (steps 401 and 402), an antenna setting command for fixing the diversity circuit to the antenna showing relatively strong sensitivity is sent to the diversity circuit.

Then, the lock of the PLL is waited (step 403), and the quality of the reception state is judged (step 40).
5). If the reception state is not good, the PLL data is updated to the next channel (step 406), and when it is determined that the reception state is good, the seek operation is stopped (step 407). By the way, if there is no seek instruction in (step 401), normal processing is performed (step 408).
However, since this point is not directly related to the present invention, its detailed description is omitted.

FIG. 5 shows the operation on the side of the diversity circuit provided in the diversity receiver.
The instruction to fix the antenna from the system microcomputer side (the antenna defined as No. 1 here: n = 1)
Received and fixed to the antenna (step 501).
~ 503). If there is no instruction to fix the antenna, a normal process is performed (step 504), and the antennas are sequentially switched at a predetermined timing to select an antenna in a good reception state.

[0006]

By the way, in the above-mentioned conventional diversity receiver, the seek operation is performed with the antenna having a relatively high sensitivity fixed, but in some cases, the seek operation is performed. There are situations where the seek operation does not stop with a fixed antenna.

This becomes remarkable when the respective antennas have different frequency characteristics.

The present invention has been made in consideration of such a situation. The best antenna is selected for each channel and the reception status of the best antenna is determined.
It is an object of the present invention to provide a diversity receiver that can perform a seek operation more reliably by stopping the seek operation if it is a good station.

[0009]

The invention according to claim 1 is
A diversity circuit that can select any antenna from a plurality of antennas, a tuner that demodulates a received broadcast wave received through the selected antenna, and the start of tuning of another broadcasting station that has a good reception state A diversity receiver including a tuning start means for commanding and a controller for receiving a command from the tuning start means and controlling the reception frequency of the tuner so as to sweep the reception band, wherein the diversity circuit is ,, detecting the antenna showing the best reception state at each frequency selected by the sweep operation of the control unit based on the reception state of each antenna, the control unit,
The selected frequency in the detected antenna
The reception level of the frequency is judged to be a predetermined value.
In the case of good stations above, stop the sweep operation,
If the frequency is not the good station, continue the sweep operation.
It is characterized by continuing .

According to the present invention, when there is a seek instruction, the diversity circuit detects the antenna showing the best reception state at each frequency set by sweeping based on the reception state of each antenna, and the control unit detects it by the diversity circuit. To determine the best antenna reception
For example, even if the respective antennas have different frequency characteristics, the best antenna can be selected, and the receivability of the selected best antenna can be determined. In addition, even when the reception state of each antenna changes every moment, it is possible to always determine the receivability of the best antenna.

According to a second aspect of the present invention, the diversity circuit determines the switching timing of the antenna based on a synchronization signal included in a received broadcast wave.

According to the present invention, since the diversity operation is performed by the diversity circuit based on the synchronizing signal, it is possible to accurately synchronize with the received signal.

According to a third aspect of the present invention, the received broadcast wave is a television signal, and the synchronizing signal is a vertical synchronizing signal and a horizontal synchronizing signal.

According to the present invention, since the diversity operation is performed by the diversity circuit during the vertical synchronizing period (blanking period) determined based on the vertical synchronizing signal and the horizontal synchronizing signal of the television signal, the receiving state of the television signal is obtained. The determination condition of is uniformized, and the seek operation is performed stably.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the diversity receiver of the present invention. As shown in the figure, the diversity receiver outputs PLL data for setting the reception frequency in the TV tuner 10, and SD (Station) from the TV tuner 10.
A system microcomputer 20 is provided for making a decision on the Detector signal. It should be noted that the SD signal is a signal indicating a reception state, and in this embodiment, the audio IF level or the video I level is used.
A signal indicating whether the F level is equal to or higher than a predetermined value is used as the SD signal.

The TV tuner 10 is adapted to receive an RF signal from any of the first to fourth antennas 1 to 4 switched by the switching circuit 30.

Video IF output from the TV tuner 10
When the signal is detected by the video detection unit 50, the RGB signal and the synchronization signal are separated by the synchronization separation unit 60 and output to the display (DSP) side not shown.

The audio IF signal output from the TV tuner 10 is detected by the audio detector 70 and output from the speaker 80.

Further, the output from the video detection section 50 is the level detection / comparison section 91 of the diversity circuit 90.
The level detecting / comparing unit 91 detects / compares the levels of the video signals and outputs information indicating the best antenna number to the switching timing determining unit 92. This switching timing determination unit 92
Are the first to fourth antennas 1 to 4 that form the switching circuit 30.
The timing for outputting a switching signal for selectively switching is determined. In the present embodiment, the switching timing of each antenna by the switching timing determination unit 92 is determined based on the horizontal / vertical synchronization signal supplied from the synchronization separation unit 60 that separates the horizontal / vertical / synchronization signals.
In the present embodiment, the switching of the antennas 1 to 4 is performed during the vertical blanking period.

The sync signal (X) from the sync separation unit 60 is also taken into the system microcomputer 20, so that the system microcomputer 20 receives it during the antenna switching operation by the diversity circuit 90. It does not judge the level. Further, the system microcomputer 20 can supply a reset signal (Y) for initializing the operation of the diversity circuit 90 to the diversity circuit 90.

Next, the operation of the diversity receiver having the above configuration will be described with reference to FIGS.

First, FIG. 2 is a flow chart showing the operation of the system microcomputer 20. When a seek start signal for selecting a good station is taken into the system microcomputer 20 by an instruction from an operation unit (not shown), the system is started. Microcomputer 20
Outputs PLL data for selecting an arbitrary channel to the TV tuner 10 (step 20).
1,202). At this time, in order to return the diversity circuit 90 to the initial state, the system microcomputer 20 outputs a reset signal (Y) to the diversity circuit 90.

PL until the tuning frequency stabilizes
L lock weight (step 203) and sync signal lock weight until the sync signal is extracted (step 20)
After a wait time consisting of 4) and 4), it is determined whether or not it is the blanking period of the received signal (step 205). Here, if it is not the blanking period, it is determined whether or not the reception state is good (step 206), and if it is the blanking period, the subsequent processing is suspended until the blanking period ends.

If it is determined in step 206 that the reception state is not good (NO in step 206), the PLL data is updated to select the next channel,
Each processing of step 202 to step 206 is continuously performed. If it is determined in step 206 that the reception state is good, the channel selection frequency is fixed and the seek operation ends. (Step 208). If there is no seek instruction in step 201, the normal processing is performed (step 20).
9) However, since such normal processing is not the gist of the present invention,
The description is omitted.

On the other hand, on the side of the diversity circuit 90, the presence or absence of the reset input (Y) is detected as shown in FIG. If there is a reset input (Y), n = 1, and during the blanking period, the switching signal is output from the switching timing determination unit 92, and the nth antenna (in this case, the first) is selected. The switching circuit 30 is controlled as described above.
Next, the level detection / comparison unit 91 compares the level of the selected antenna with the level of the previously selected antenna (initial value = 0) (pedestal level comparison), and the antenna number of the higher level and The level is retained (stored). Such processing is repeated for the number of antennas (four antennas in this example) (steps 306 and 30).
By 7), the antenna showing the best reception condition is fixed,
The best antenna is selected in step 308. Therefore, the diversity circuit 90 determines the best antenna during the blanking period, and the system microcomputer 20 determines the reception state after the blanking period.

If there is no reset input in step 301, the normal processing is performed (step 309), but this normal processing is the same as the conventional structure, and therefore its explanation is omitted.

As described above, in the present embodiment, when a seek instruction is given, the diversity circuit 90 causes any one of the first to fourth antennas 1 to 4 showing the best reception state at the frequency set by the sweep. A process of detecting based on the reception state of each of the antennas 1 to 4, and the system microcomputer 20 determining the reception state of the best antenna detected by the diversity circuit 90 is performed for each channel set during seek. Therefore, the antenna with the best reception state can always be determined. Therefore, the seek operation is performed more reliably.

[0028]

As described above, according to the diversity receiver of the present invention, when a seek instruction is given, the diversity circuit receives the antenna showing the best receiving state at the frequency set by the sweep of each antenna. Since the control unit determines the reception state of the best antenna detected by the diversity circuit based on the state, the antenna in the best reception state can be set for each channel, and the accuracy of the seek operation is improved. This is particularly effective when the antennas have different f characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a diversity receiver of the present invention.

2 is a flow chart for explaining the operation of a system microcomputer of the diversity receiver of FIG.

FIG. 3 is a flowchart illustrating an operation of a diversity circuit of the diversity receiver of FIG.

FIG. 4 is a flowchart for explaining the operation of the system microcomputer in the conventional diversity receiver.

FIG. 5 is a flow chart for explaining the operation of the diversity circuit in the conventional diversity receiver.

[Explanation of symbols]

1-4 antennas 1 to 4 10 TV tuner 20 system microcomputer 30 switching circuit 50 Video detection section 60 Sync Separator 70 Voice detector 80 speakers 90 Diversity circuit 91 Level detection / comparison section 92 Switching timing determination unit

Front page continuation (72) Inventor Masahiro Kikawa 25 Nishimachi, Kawada City, Saitama Prefecture 1 Nishimachi, Pioneer Co., Ltd. Kawagoe factory (72) Hideshi Ishiyama 25 25 Nishimachi, Kawagoe City Saitama Prefecture 1 Kawagoe, Pioneer Corporation Inside the factory (72) Inventor Hitoshi Konishi 1-4-1 Chuo, Wako-shi, Saitama Prefectural Technology Research Institute Ltd. (72) Inventor Takeshi Imai 4-1-1 Chuo, Wako-shi, Saitama Pref. (56) References JP-A-1-195714 (JP, A) JP-A-4-188909 (JP, A) JP-A-5-75397 (JP, A) JP-A-5-284070 (JP, A) Kaihei 6-13924 (JP, A) JP-A-9-93170 (JP, A) Actual Kaihei 5-55623 (JP, U) Actual Kaihei 6-15343 (JP, U) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H04B ⁷ /02-7/12 H04L 1/02-1/06 H03J 5/00-5/02 H03J 5/14-5/30 H03J ⁷ /00-7/32 H04N 5/38-5/46

Claims (3)

(57) [Claims] 1. A diversity circuit capable of selecting an arbitrary antenna from a plurality of antennas, a tuner for demodulating a received broadcast wave received through the selected antenna, and a broadcast station of another broadcasting station having a good reception state. A diversity receiver comprising a tuning start means for instructing the start of tuning, and a controller for receiving a command from the tuning start means and controlling the reception frequency of the tuner so as to sweep the reception band, The diversity circuit detects an antenna indicating the best reception state at each frequency selected by the sweep operation of the control unit based on the reception state of each antenna, and the control unit is the detected antenna. Election
Determine the reception status of the tuned frequency and receive the frequency
In the case of a good station whose level is above a specified value, the sweep motion
If the operation is stopped and the frequency is not the good station,
A diversity receiver characterized by continuing the sweep operation . 2. The diversity receiver according to claim 1, wherein the diversity circuit determines the switching timing of the antenna based on a synchronization signal included in a received broadcast wave. 3. The diversity receiver according to claim 1, wherein the received broadcast wave is a television signal, and the synchronizing signal is a vertical synchronizing signal and a horizontal synchronizing signal.