JPH0337769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving device, and more particularly to a receiving device for receiving specific broadcast programs such as emergency broadcasts.

Emergency broadcasts to notify of earthquake occurrences, traffic information, etc.
At the start and end of a specific program, including a weather forecast, etc., an FSK signal is sent as an identification signal, for example, two low frequency signals, one of which is a so-called mark and the other a space, which are combined to form a digital signal. The following method is known.

A receiver block that listens to only such specific programs is shown in Figure 1, and the RF (radio frequency) input is
After being amplified by an RF amplifier 1, it is mixed with a local oscillator signal from a local oscillator 3 in a mixer 2 and converted into an IF (intermediate frequency) signal. This IF signal is input to a detector 5 via an IF amplifier 4 and demodulated into an AF (audio frequency) signal. This AF signal is applied to an AF amplifier 7 via a switch 6, amplified, and then drives a speaker (not shown).

BPFs (band pass filters) 8 and 9 are provided to detect the FSK signal from the wave output of the detector 5, and both BPFs 8 and 9 extract low frequency signals corresponding to marks and spaces, respectively. be. Both extracted outputs are detected by diode detectors 10 and 11 and applied to a differential amplifier 12 to obtain a difference signal between both signal levels. This difference signal is level-compared with the reference level from the reference signal generator 13 in the comparator 14, and the on/off of the switch 6 is controlled by the comparison output.

In this configuration, the switch 6 is normally open and the speaker does not sound. Here, when an FSK signal indicating the start of a specific program arrives, frequency signals corresponding to marks and spaces are extracted by BPF 8 and 9, respectively, and detected by detector 1.
Detected at 0 and 11. In the differential amplifier 12, the level difference between the two detection outputs (this corresponds to the ratio of marks and spaces) is compared with a predetermined reference level, and the switch 6 is closed. In this way, it becomes possible to listen to a specific program.

An FSK signal is sent out at the end of a specific program, but
The difference between the detection outputs of the detectors 10 and 11 becomes a level different from that at the start, and this level is detected by the comparator 14 to open the switch 6. In this way, no sound is output during standby, but the sound is output in response to the start signal of the source you want to listen to, and when that ends, the system automatically returns to the standby state again.

With such a conventional configuration, it is possible to detect the presence or absence of a specific program on only one broadcast station and listen to it, but since it is necessary to set the receiver on the frequency of the broadcast station and wait, it is possible to listen to the program on other stations. The disadvantage is that you cannot listen to specific programs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a receiving device that can know the start of a specific program of another station even if it is receiving a program of any broadcast station.

In addition to the first receiving system that receives broadcasts in a predetermined frequency band according to a tuned frequency, the receiving device of the present invention has a second receiving system that sweeps frequencies within the predetermined frequency band without changing the tuned frequency. detecting means for identifying the transmission frequency of the predetermined broadcast station by detecting a start identification signal transmitted at the start of a specific program from a predetermined broadcast station; It is characterized by including a notification means for announcing the frequency.

An embodiment of the present invention will be described below with reference to FIG. The original receiving system is composed of RF amplifier 1, mixer 2, IF amplifier 4, detector 5, and AF amplifier 7, and in addition, a receiving system for FSK signal detection with approximately the same configuration as in Figure 1 is added. has been done. That is, RF amplifier 1a, mixer 2a,
A reception system including an IF amplifier 4a, a detector 5a, BPFs 8 and 9, diode detectors 10 and 11, a differential amplifier 12, a reference signal generator 13, and a comparator 14 is provided.

The original receiving system is a so-called PLL (Phase Locked Loop) frequency synthesizer tuner system, which is a well-known configuration that allows for preset tuning as well as sweeping reception frequency tuning. PLL circuit is VCO
(Voltage controlled oscillator) 3, LPF (low pass filter)
15, phase comparison 16, programmable frequency divider 1
7 and reference oscillator 18, VCO3
The output of the LPF 15 becomes a local oscillation signal, and the output of the LPF 15 is used to control the tuning frequency of the tuning circuit of the RF amplifier 1. The frequency division ratio of the programmable frequency divider 17 is controlled by the controller 19, allowing sweep tuning and preset tuning.

The same goes for the receiving system for identifying FSK signals.
PLL synthesizer method, VOC3a, LPF
15a, a phase comparator 16a, a programmable frequency divider 17, and a reference oscillator 18a. VCO3
The output of a becomes the local oscillator signal of mixer 2a, and the LPF
The output of the RF amplifier 1a becomes the tuning frequency control signal of the RF amplifier 1a, and the controller 19 outputs it to the frequency divider 17.
The frequency division ratio of a is controlled. This frequency division ratio control method is performed in such a way that it is possible to sweep the frequency within the reception frequency band (referring to the AM band, FM band, etc.), but it is also possible to sweep the frequency over the entire band. It may also be possible to scan only the frequencies corresponding to stations whose service area is the district.

When the FSK signal is identified by this receiving system, the output from the comparator 14 is sent to the controller 19, and the change in the frequency division ratio of the frequency divider 17a is temporarily stopped.

Further, a display signal is sent from the controller 19 to the display 20, thereby displaying the current receiving frequency of the original receiving system. Furthermore, indicators 21 to 24 are provided, and the indicator 2 corresponds to the receiving frequency at the time of detecting the FSK signal.
The lighting of one of the lamps 1 to 24 is controlled.

In such a configuration, it is assumed that the original receiving system is receiving one broadcast station by a preset channel selection operation. In this case, the receiving system for FSK signal identification is placed in a receiving frequency sweep state by the controller 19, and the frequency within the receiving band is swept. When a specific program starts being broadcast from a predetermined broadcasting station during this sweep, an FSK signal is sent out at the start, so this receiving system detects this and a detection signal is generated from the comparator 14. Since the frequency division ratio of the programmable frequency divider 17a at this time corresponds to the frequency of the specific broadcasting station, one of the indicator lamps 21 to 24 corresponding to this frequency station
The lighting is controlled. When this FSK signal identification is performed, the frequency sweep is stopped for a predetermined period of time, the lamp continues to be lit, and a specific program can be announced. If this lamp is associated with a preset button for the original reception system, the user can immediately operate the preset button to listen to a specific program. Of course, when a specific program ends, the display lamp is turned off by the FSK signal at the end.

In addition, instead of or in conjunction with the notification of a specific station, the controller 19 sets a frequency division ratio corresponding to the frequency of the specific station in the frequency divider 17, and forces the original reception system to receive the specific station. You can do it like this.

Of course, the method of announcing a specific program may be an auditory method as well as a visual method, and the original receiving system is not limited to the preset channel selection configuration. Furthermore, not only the FSK signal but also other types of signals can be used as the identification signal of a specific program, and in this case, a detection configuration according to the signal type may be adopted.

In the above embodiment, the start and end signals of a specific program control the lighting of the display at the position corresponding to the preset button of the preset station, but the specific program is divided into emergency broadcasts and regular programs such as news and traffic information. It is also possible to use two such detection/judgment circuits to forcibly switch the station that has been listened to to the emergency broadcast station during an emergency broadcast, and to only display a notification during a normal program.

Although the configuration is shown as a receiver only, it can also be applied to products that are integrated with a tape deck, etc., or to car stereo equipment, where a specific program can be announced even while the tape is being played, and even radio reception. It can be made to switch.

As described above, according to the present invention, even when the original receiving system is receiving normal broadcasting, it is possible to detect a specific program broadcasting station using another receiving system, so that the user can detect the specific program broadcasting station by using the other receiving system. This has the advantage of making it easier to tune to a plurality of specific program broadcast stations as needed while listening to the program.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional receiving apparatus, and FIG. 2 is a block diagram of a receiving apparatus according to the present invention. Explanation of symbols of main parts, 3...VCO, 14...
... Comparator, 15 ... LPF, 16 ... Phase comparator, 17 ... Programmable frequency divider, 19 ...
...Controller, 21-24...Display device.

Claims (1)

[Claims] 1. In addition to the first receiving system that receives broadcasting in a predetermined frequency band according to the tuned frequency, a second receiving system sweeps the frequency within the predetermined frequency band without changing the tuned frequency. detecting means for identifying the transmission frequency of the predetermined broadcast station by detecting a start identification signal transmitted at the start of a specific program from a predetermined broadcast station; 1. A receiving device comprising: announcing means for announcing a frequency. 2. The first reception system has a configuration in which the channel can be selected freely by a preset button, and the notification means displays the specific program at the preset button corresponding to the transmission frequency identified by the detection means or at a position corresponding to this button. 2. The receiving device according to claim 1, wherein the receiving device displays a display indicating the start of broadcasting.