JPS5846737A - Tracking system for same program - Google Patents

Abstract

PURPOSE:To ensure the automatic reception in the best condition while the service areas of plural stations which transmit the same program are moving, by extracting the wave detection output of a signal receiver which is receiving a station having a higher receiving level among the output signals showing the same program. CONSTITUTION:A signal receiver 13 synchronizes with either one of the stations and transmits a wave detecting signal S1. In this case, if a signal receiver 14 synchronizing with another station transmits a wave detection signal S2, this signal S2 is supplied to a subtractor circuit 17 and an adder circuit 18 through BPF15 and 16 respectively. Here the full-wave rectification is given to the output of the circuit 18 through a rectifying circuit 22, and the division is controlled in terms of DC to prevent the decision from affected by the modulation factor. After this division, a decision output circuit 24 transmits the program received by two receivers to a control circuit 26 by the signal of ''1'' or ''0''. The circuit 26 delivers the wave detection output of the receiver which is receiving the station of a higher receiving level from a terminal 29 via a switching circuit 25 in the case of the same program.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a same program tracking system, and more specifically, the present invention relates to a same program tracking system, and more specifically, in a mobile object such as a car, it selects a plurality of stations transmitting the same program as it moves and obtains the best reception condition. Concerning maintaining the same program-tracking system.

When receiving broadcast radio waves while moving in a car, ship, or aircraft, for example, when receiving broadcast waves while driving from point A to point B in Figure 1, the transmitted radio waves are transmitted at each moving point. The situation will change. When all broadcast stations 1 to 7 are broadcasting the same program at the same time,
A listener who departs from point A can receive the broadcast program by tuning into broadcasting station 1, but as the listener approaches point C, the reception condition worsens, and as the listener advances further to point C, the reception condition worsens. At this point, you have already moved out of the service area of broadcasting station 1, and if you were tuned to the transmission frequency of broadcasting station 1, you would no longer be able to receive it. Therefore, if you wish to continue receiving the same program, , the user must retune to broadcast station 2 and confirm that the same program is being broadcast before changing the receiving station.Such operations are particularly troublesome when the listener is a driver. There is also a danger in terms of distraction.

When reaching point E in Figure 1, even though the radio waves from broadcasting station 4 are the strongest, the listener still hears the weak level of the broadcast because it is within the service area of broadcasting station 3. It also continues to receive radio waves from station 6.

In addition, in a case like point F in Figure 1, broadcasting stations 5 and 6
．． Since the service areas of and 7 overlap, the station with the strongest level changes every moment, and if there are obstacles nearby, multipath distortion will occur.

In view of the above drawbacks, the present invention provides a same program tracking system that can always automatically select and receive the station with the highest level when moving across the service areas of a plurality of stations transmitting the same program. The present invention will be described in detail below with reference to Examples.

FIG. 2 is a block diagram showing an embodiment of the same program tracking system according to the present invention. In FIG. 2, a distributor 12 distributes radio waves received from an antenna 11 to receivers 16 and 14. Band pass filters 15 and 16 pass only frequency components suitable for comparison of detection outputs S1 and S2 of receivers 13 and 14, respectively. The subtraction circuit 17 subtracts the output of the band pass filter 15 from the output of the band pass filter 15.
The output of the filter 16 is subtracted (Sl-82) and is supplied to the amplifier 19, and the adder circuit 18 adds the outputs of the band pass filters 15 and 16 and supplies (S1+82) to the amplifier 20. The division circuit 21 divides the output signal (Sl-32) of the subtraction circuit 17 by the (S1+82) component that has been double-wave rectified (peak detected) by the rectifier circuit 22, and the amplifiers 19 and 20 accurately perform the division. Amplify it to an appropriate level for the purpose.

The rectifier circuit 23 double-wave rectifies the output of the divider circuit 21 and sends it to the determination output circuit 24, which determines whether or not Sl and 82 have the same content and supplies the result to the control circuit 26. do. The switching circuit 25 is controlled in response to the control circuit 261/1 determination output circuit 24, and either the detection output S1 or S2 of the receiver is outputted as an audio signal via the amplifier 28.

The memory 27 is for storing stations broadcasting the same program.

With the above configuration, the present invention operates as follows.

One of the receivers 13 or 14 is controlled by a control circuit 26 to always scan for frequencies.

For example, if the receiver 13 is a fixed receiver that tunes to a certain station, the receiver 14 sequentially switches frequencies and scans to tune to stations other than the fixed frequency. Then, a comparison is made with the detection output of the receiver 13 for each tuned frequency.

When the receiver 15 is tuned to one of the stations and sends out the detected output S1, and the receiver 14 tuned to any other station sends out the detected output S2, the output signals S1 and S2 are as follows.
passing through band pass filters 15 and 16, respectively;
The signal is supplied to a subtraction circuit 17 and an addition circuit 18. The output of the subtraction circuit 17 changes depending on whether the programs being received by the receivers 13 and 14 are the same. In other words, when two receivers are receiving the same program, each detection output is similar and the level decreases significantly, but when two receivers are receiving different programs, the level does not decrease. , Even if there is an upset, it is only for a short time and its occurrence is thought to be random. Therefore, depending on the output level of the subtraction circuit 17, 2
It can be determined whether the programs being received by the two receivers are the same.

However, the accuracy of this determination may be affected by the degree of modulation of the received radio waves. Therefore, in the present invention, the output of the adder circuit 1B is subjected to double-wave rectification (peak detection) by the rectifier circuit 22 to control the division in a DC manner, thereby preventing the judgment from being influenced by the degree of modulation. After this division has been performed, the determination output circuit 24 sends a logic 1 or 0 signal to the control circuit 26 to determine whether the programs being received by the two reception machines are the same.

When the output of the determination output circuit 24 is a signal indicating that the program is the same, the control circuit 26 outputs the detection output of the receiver (1'5 or 14) that is receiving the station with the higher reception level. It is switched by the switching circuit 25 and supplied to the output terminal 29. At this time, the memory 27 stores the stations that are transmitting the same program as a result of frequency scanning, and the judgment output circuit 24 is controlled so that the station with the strongest level among them is finally selected. If the output is a signal indicating a different program, the control circuit 26 changes the tuned frequency of the receiver 14 to that of the next station, and repeats the above operation.

As described above, according to the same program tracking system of the present invention,
It is possible to receive the same program while automatically maintaining it in the best condition while moving in a car or the like through the service areas of a plurality of stations transmitting the same program. As a result, conventionally,
This eliminates the hassle of having to make adjustments every time you move. Also, without using the distributor illustrated in Fig. 2, it is possible to place the antenna at a distance of two
By providing this, it is also possible to further reduce the multipath distortion described above.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the present invention in detail, and FIG. 2 is a block diagram showing one implementation of the same program tracking system according to the present invention. Patent applicant Tararion Co., Ltd.

Claims (2)

[Claims] (1) Two receivers: - A subtraction circuit that outputs the difference between the detection outputs of the two receivers, and an addition circuit that outputs the sum of the detection outputs of the two receivers. a division circuit that divides the output of the subtraction circuit by the output of the addition circuit; a determination circuit that determines whether the contents of the detection outputs of the two receivers are the same based on the output of the division circuit; and the determination circuit. and a control circuit for transmitting the detection output of one of the receivers from a thicker reception level when the detection outputs of the two receivers have the same content in response to the detection output of the two receivers. . (2) The one of the two receivers is controlled by the control circuit to sequentially switch the tuning frequency and perform the determination operation by the determination circuit.
Same program tracking system described in section 1).