JPS61290813A - Fm receiver - Google Patents

Abstract

PURPOSE:To facilitate prevention of omission of hearing of traffic information of automatic selection of broadcasting stations etc. by providing a searching circuit that makes searching of a station that broadcasts traffic information. CONSTITUTION:A searching circuit for receiving traffic information is provided. The searching circuit is provided with an antenna 1 in common and provided with a front end 2s, an intermediate frequency amplifier 3s, a detector 4s, a traffic information decoder 17s and a microcomputer 8s, and has function to search and detect traffic information signals SK, DK, BK and to select broadcasting stations. A microprocessor 14s is connected to a microprocessor 14 by an I/O circuit and enabled to give and receive search command to give and receive the frequency data of broadcasting station of traffic information. Thus, by adding the searching circuit, an FM reception section consisting of 1-17 selects a broadcasting station of frequency designated by a keyboard 15 and receives the broadcast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an FM receiver having a function of receiving traffic information broadcasts.

[Prior Art] In recent years, there has been a demand for a traffic information system to alleviate traffic congestion, and in West Germany, API broadcasting has been adopted as a traffic information system.

This API broadcasting system has a three-step system configuration using SK, DK, and BK double signals. The outline of each system will be explained below with reference to the frequency spectrum of the broadcast waves of the API system broadcast station shown in FIG.

(1) Broadcast system using SK double signal FM broadcast stations that adopt this system have a 57K Hz subcarrier as an identification signal, frequency modulate this to the main carrier, and broadcast.
By detecting the presence or absence of KHz, the FM broadcasting station broadcasting traffic information can be distinguished, and the traffic information can be obtained by receiving broadcasts from the F'M broadcasting station.

@) Broadcasting system using DK double signal FM broadcast stations that adopt this system, in addition to the above-mentioned traffic information broadcasting station identification signal using SK double signal, broadcast between general program broadcasts (music, news, etc.) Sporadic (1
SK double signal 5 for traffic information broadcasted about 4 times per hour)
Broadcast at 7KHz plus DK double signal. This DK double signal SK double signal 57K H2 is amplitude-modulated with 125H2, and the subcarrier is frequency-modulated onto the main carrier, and the traffic information is broadcast by detecting the DK double signal amplitude-modulated to 57KHz on the receiver side. be able to identify things.

This DK double signal identification makes it possible to distinguish between general program broadcasts and traffic information broadcast in between, and on the receiver side, for example, even when the received sound m is turned down, the DK double signal detection can be used to increase the volume. This prevents you from missing traffic information, and makes it possible to switch to traffic information reception by detecting a DK double signal while playing a cassette tape.

(3) Broadcasting system using BK double signal FM broadcasting stations that use this system broadcast local traffic information and different traffic information for each region, so BK double signal SK low signal is used as a regional identification signal. 57KH
2 with amplitude modulation applied. The modulation frequency of each regional BK multiplied signal is set to an integer fraction of 57KH2,
23.75 Hz for API system, 28.27
Hz, 34.93Hz, 39.58Hz
It is divided into six categories: , 45.6Hz, and 53.98Hz. On the receiver side, by identifying the BK double signal, it is possible to receive regional traffic information.

A conventional FM receiver for a traffic information system as described above has a configuration shown in FIG. The figure shows a general P
It is configured as an FM receiver with an LL circuit, and has an antenna 1. Front end 2° intermediate frequency amplifier 3. FM detector4. Multiplexer 5. Low frequency amplifier6. A receiving circuit of the speaker 7 is provided with a PLL tuning circuit using a microcomputer 8, using the local oscillator of the front end 2 as a voltage llI controlled oscillator<VCO. The microcomputer 8 includes a divider 9 that frequency divides the vCO signal of the local oscillator, a phase comparator 10 that compares the phase of this frequency-divided signal with a reference frequency signal, and converts this phase comparison output into a voltage signal to control the local oscillator. It has a PLL circuit consisting of a low-pass filter 11 that obtains a voltage.

The microcomputer 8 obtains the reference frequency signal by selecting the clock of the crystal oscillator 12 with the reference selection circuit 13, and this selection is performed by the tuning control signal output from the microprocessor 14.

The microprocessor 14 performs tuning processing in response to a tuning command from the keyboard 15, displays the selected tuning frequency on the display 16, and also displays the SK, BK, and DK multiplied signals from the traffic information signal decoder 17. Performs channel selection control. The decoder 17 detects the presence or absence of SK and DK from the detection output of the detector 4.
Detects the presence or absence of BK. In addition to the selected channel frequency, the display 16 displays SK low signal DK and BK double signal information.

[Problems to be solved by the invention] In conventional FM radio equipment having a traffic information receiving function, it is difficult to select a broadcasting station broadcasting traffic information (SK low signal and broadcast time identification (DK), Broadcast identification of current location (BK
), but in order to obtain the desired traffic information as the receiving position changes, it is necessary to give a search command using the keyboard each time, and in order to select to receive other traffic information, it is necessary to give a search command each time the desired traffic information is received. It was inconvenient to use, as it temporarily made it impossible to receive stations.

[Means and effects for solving the problems] The present invention has been made in view of the above problems, and allows reception of FM broadcasts that have been added with traffic information identification signals switched to the corresponding broadcasting station by detecting the identification signals. an FM receiving section, and a search circuit that searches for a broadcasting station that is currently broadcasting FM by adding the identification signal, constantly stores tuning data of the said broadcasting station, and supplies it as tuning data to the FM receiving section as needed. This system is equipped with the following, and is capable of constantly searching for a broadcasting station that is currently broadcasting traffic information in the area while being received by the FM receiver, and making it possible to use the data for receiving traffic information.

[Example] FIG. 1 is a circuit diagram showing one practical example of the present invention.

In addition to the configuration of the FM receiving section 1 to 17 in FIG. 3, this figure is provided with a search circuit for receiving traffic information.

This search circuit uses a common antenna 1, and includes a front end 2s, an intermediate frequency amplifier 3s, a detector 4s, a traffic information signal decoder 17s, and a microcomputer 8S. In the same way, traffic information signals SK, DK, BK are searched according to the search command.
It has functions for searching and detecting signals and selecting the relevant broadcasting station.

The microprocessor 14s is coupled to the microprocessors 14 and 110 circuits, and is capable of sending and receiving search commands and sending and receiving traffic information broadcasting station frequency data.

By adding such a search circuit, the FM receiving section consisting of 1 to 17 selects and receives the broadcasting station of the frequency specified by the keyboard 15 as in the conventional case. On the other hand, the search circuit section searches for a broadcasting station broadcasting traffic information in parallel with the above reception, and upon completion of the search, the frequency data or channel data of the broadcasting station (one station or multiple stations) is sent to the microprocessor 14s. The microprocessor 14 stores the data in memory and displays it as necessary. 116.

Therefore, while maintaining normal reception by the FM receiver,
Broadcasting stations currently broadcasting traffic information in a region are constantly searched by a search circuit, and by adding a search circuit having such a function, the following uses can be made.

(1) While the broadcast of the current receiving station is open, the search circuit performs an SK double signal search and then a region-specific BK signal search, and stores the data of these searched broadcast stations in a preset memory for mobile reception. You can see the currently receivable broadcast stations on the display.

Q) When a DK signal is detected in the above search state, reception is switched to the corresponding broadcast station automatically or by key operation to prevent traffic information from being missed, and when the traffic information ends, it is automatically switched to the corresponding broadcast station or by key operation. broadcasting station.

(3) Monitor the presence or absence of the SK double signal or the search stop signal so that when the signal strength of the current receiving station becomes weak, you can instantly switch to another broadcasting station in the current area.
J can be controlled.

(4) Since the current receiving station designation and search can be performed in parallel, two or more 1M stations can be kept on standby at the same time during AM reception or tape playback, increasing the tuning range.

In addition, in the embodiment, the microcomputers 8, 8
The case where two PLL circuits are used is shown, but it goes without saying that one microprocessor can control two PLL circuits.

[Effects of the Invention] As described above, according to the present invention, a search circuit is provided in addition to the conventional FM receiving section to search for stations broadcasting traffic information, so that it is possible to avoid missing traffic information. You can easily prevent such broadcasting and automatically select the relevant broadcasting station.
This has the effect of improving usability.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of the present invention, Figure 2 is a frequency spectrum of broadcast waves employing a traffic information system,
FIG. 3 is a conventional circuit diagram. 2.2S...Front end, 3,3S...Intermediate frequency increase IIIAffJ, 4, 4s...Detector, 8,8
S...Microcomputer, 14.14s...Microprocessor, 15...Keyboard, 16...
Display, 17.17s...Traffic information signal decoder. Patent Applicant Pioneer Co., Ltd. Agent Nobu Kobashi Patent Attorney Shinbu Murai

Claims (1)

[Claims] An FM receiving section that can switch from an FM broadcast to which an identification signal of traffic information is added to the corresponding broadcasting station by detecting the identification signal, and an FM receiving section that searches for a broadcasting station that is currently broadcasting FM with the identification signal added to the station. An FM receiver comprising: a search circuit that constantly stores tuning data and supplies it as tuning data to the FM receiving section as needed.