JPH08213923A - Fm multiplex broadcast receiver - Google Patents

Abstract

PURPOSE: To effectively use a display device by displaying information of an FM multiplex broadcast usually even in the voice mode in order to utilize the display device effectively in the on-vehicle FM multiplex broadcast receiver in which information relating to many modes cannot at once be displayed. CONSTITUTION: The FM multiplex broadcast receiver 1 provided with a cassette deck 20 providing an output of voice information independently of an FM multiplex broadcast, a display device 18 displaying display information of the FM multiplex broadcast or display information of the cassette deck 20 and a control section 14 controlling output start of voice information includes a RAM 17 storing the display information of the FM multiplex broadcast and a control circuit 15 displaying the display information of the cassette deck 20 based on the operation of the control section 14 for a prescribed time and displaying the display information of the FM multiplex broadcast stored in the RAM 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM multiplex broadcasting receiver.

[0002]

2. Description of the Related Art FM multiplex broadcasting is a broadcasting system for providing a new service by multiplexing digital signals such as characters, graphic information, data, etc. in a gap between radio waves of FM audio broadcasting (see Japanese Patent Laid-Open No. 3-6926). ). This system has been put to practical use in RDS in Europe and RBDS in the United States. Even in Japan, some broadcasting stations are preparing for the start of services in April 1995. This is for displaying news, weather forecasts, complementary programs, music programs, traffic information and emergency broadcasts with a display of 15.5 characters x 2 lines.

[0003]

In a small-sized FM multiplex broadcast receiving apparatus mounted on a vehicle, the number of characters displayed on the display unit is small, and the FM multiplex broadcast information and display information other than the FM multiplex broadcast (for example, Radio band frequency,
It is difficult to display the running state of the cassette tape, the song number, song name, date and time of the CD, etc., all at once. For example, it is not possible to know the FM multiplex broadcast information while listening to the reproduced sound of the cassette tape.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is characterized by an F that receives an FM broadcast.
An M reception circuit, a multiplex signal detection circuit for detecting the first display information multiplexed in the FM broadcast by the FM reception circuit, and an audio output means for outputting audio information unrelated to the first display information, FM multiplex broadcasting having a control circuit for outputting the second display information related to the audio output means, a display device for displaying the first or second display information, and a key for operating the output start of the audio information. The receiving device includes a storage unit for storing the first display information, and the control circuit displays the second display information for a predetermined time based on an operation of the key and then stores the second display information in the storage unit. And displaying the first display information.

[0005]

When the mode is other than the FM multiplex broadcasting, the voice reproduces the mode, the screen displays the information of the mode for a while, and then the display changes to the FM multiplex broadcasting information display.

[0006]

[Embodiment] An embodiment of the present invention is a cassette deck, FM / M
This will be described with reference to the drawings, which is applied to the FM multiplex broadcast receiving apparatus (1) equipped with W radio and FM multiplex broadcast.

FIG. 1 is a block diagram showing the main part of the embodiment. (2) is an FM receiving circuit, which comprises an FM front end (3), an FM-IF detector (4) and an FM stereo demodulation circuit (5). (6) is a MW receiving circuit, M
It is composed of a W tuner (7) and a MW-IF detector (8). FM front end (3) and MW tuner (7)
Amplifies the signal received from the antenna (9) into a high frequency signal, mixes the high frequency signal and the oscillation signal from the PLL circuit (10) and outputs an intermediate frequency signal (IF). FM
The IF detector (4) and the MW-IF detector (8) perform FM detection and MW detection on the intermediate frequency signals output from the FM front end (3) and the MW tuner (7), respectively. The FM stereo demodulation circuit (5) uses the stereo composite signal input from the FM-IF detector (4) to generate L
The channel and R channel signals are reproduced and each channel signal is output. (11) is a multiplex signal detection circuit, which is a multiplexing filter (12) and a data demodulation circuit (13).
Consists of The multiplexing filter (12) removes a voice signal and a noise component from the output signal of the FM front end (3), and multiplexes the LMSK (Level cont) at 76 kHz.
rolled Minimum Shift Keying) signal is extracted. The data demodulation circuit (13) demodulates the LMSK signal into a displayable data signal, removes the level fluctuation of the LMSK signal, detects the synchronization signal, removes the PN code, and performs error correction.

Reference numeral (14) is an operation unit having a plurality of keys as shown in FIG. Among these, FM multiple key (K
1), TAPE key (K2), AM / FM key (K3)
Is a key for selecting each mode. Reference numeral (15) is a control circuit, which includes an operation unit (14) and a multiple signal detection circuit (1
Each part is controlled based on 1). Reference numeral (16) is a ROM which stores a program for operating the control circuit (15). (17) is a RAM, which stores data necessary for the operation of the control circuit (15). Reference numeral (18) is a display device, which displays character data of FM multiplex broadcasting, frequency and time of AM / FM broadcasting station, and the like. The number of displayed characters is 15.5 characters x 2 lines or more in accordance with FM multiplex broadcasting.

Reference numeral (19) is a switch section, and any one of the output of the FM stereo demodulation circuit (5), the output of the MW-IF detector (8) and the output of the cassette deck (20) is controlled by the control circuit (15). Or switch the speaker (2
It is output to the amplifier circuit (22) of 1). (23) is a battery of the vehicle, and as shown by a broken line in FIG.
5), the ROM (16), the RAM (17) and the display device (18) are directly connected, and a current is constantly supplied to these. Other FM front end (3) etc. are POWER switch (24) and vehicle ignition switch (25)
Are connected in series and power is not supplied unless both switches are closed.

The power switch of the POWER switch (24) or the ignition switch (25) of the vehicle is turned off.
Then, the power supply to the FM receiving circuit (2) and the multiplex signal detecting circuit (11) is cut off, so that new information of FM multiplex broadcasting cannot be received. But,
The power supply for control such as the control circuit (15) and the RAM (17) is supplied from the battery (23) of the vehicle, so that storage and control operations are possible.

Next, the display operation of the control circuit (15) when the FM multiplex key (K1) is pressed will be described with reference to the flowchart of FIG. The variable M used in this flowchart indicates the designated mode, M = 1 is FM multiplex mode, M = 2 is TAPE mode, M = 3 is AM / FM.
Indicates that you are in mode. The variable S indicates whether or not to return the FM multiplex screen to the initial screen, and S = 1 indicates to return to the initial screen.

First, when the FM multiplex broadcast receiver (1) is connected to the vehicle battery (23) and the control circuit (15) becomes controllable, the variable M is set to 1 and the variable S is set to 1 as initial values. Yes (S1). Then, the power switch is in a standby state for waiting for both the POWER switch (24) and the vehicle ignition switch (25) to be turned on (S).
1). When the power is turned on, the timer (S17) that started counting from the time when the power was previously turned off is set to 3
Whether or not minutes have passed is checked (S3), and if 3 minutes have passed, the variable S is set to 1 (Y of S3, S4). Next, when the power is off, that is, when the variable M is checked and M = 1, FM multiplex mode processing is performed (Y and S in S5).
6), if M = 2, perform TAPE mode processing (S
7 / Y, S8), if S = 1 but S = 2, AM / FM
Mode processing is performed (N in S5, N in S7, S9). The processing in each of these modes will be described later based on the flowcharts of FIGS. When the processing of each mode ends, whether or not the mode has been changed (S10,
(S11, S12) and it is checked whether the power is turned off (S13). If neither is changed (N in S13), the processing in the original mode is continued (B). When the FM multiplex key is pressed, the variable M is set to 1 and FM multiplex processing is performed (Y in S10, S14, C). When the TAPE key is pressed, the variable M is set to 2 and the TAPE process is performed (Y in S11, S15, D). When the AM / FM key is pressed, the variable M
To 3 for AM / FM processing (Y in S12, S1
6, E). When the POWER switch (24) or the vehicle ignition switch (25) is turned off, the timer is started (Y in S13, S17, A).

The processing of the FM multiplex mode (subroutine of S6) will be described with reference to the flowchart of FIG. Power O
It is checked whether or not 3 minutes have passed after the FF, that is, whether or not the variable S is 1 (S18). If S = 1, then F
The M-multiplexed initial screen is displayed (S19). This initial screen is, for example, news, music program, weather forecast, traffic information,
9 is a display screen (FIG. 7) of a menu for selecting either a complementary program or an emergency broadcast. A menu selection process is performed based on the operation unit (14) (S20), and when this is completed, the variable S is set to 0 (S21). When the FM multiplex information of the selected menu is received, this information is written in the RAM (17) (Y of S22, S23). Then, this information is read and displayed on the screen (S24, S25) (FIG. 8). FM
It may take time to receive new information of the multiplex broadcast, and if it cannot be received immediately, the previous information is displayed (N of S22, S24, S25).

The processing in the TAPE mode (subroutine of S8) will be described with reference to the flowchart of FIG. The TAPE mode screen (FIG. 9) and the TAPE mode sound are displayed for 5 seconds (N in S26 to S29). When 5 seconds have elapsed (Y of S29), the voice continues the TAPE mode (S30), and the screen is set to the FM multiplex mode of the same processing as step S6 (S31).

The AM / FM mode processing (subroutine of S9) will be described with reference to the flowchart of FIG. The AM / FM mode screen and the AM / FM mode voice are displayed for 5 seconds (N in S32, S33, S34, S35).
When 5 seconds have elapsed (Y of S35), the voice continues the AM / FM mode (S36), and the screen is set to the FM multiplex mode of the same process as step S6 (S37).

As described above, in the modes other than the FM multiplex broadcasting, the audio reproduces the other modes, the screen displays the information of the mode for a while, and then the display changes to the information of the FM multiplex broadcasting. The display contents in the TAPE mode and the AM / FM mode are the status of the TAPE, the frequency of the receiving radio band, etc., and are not necessarily the display information that should always be displayed. Therefore, in order to effectively utilize the display device (18), it is usually intended to display the FM multiplex.

It may take several minutes to receive new FM multiplex broadcast information after the power is turned on. For this reason, the information of the FM multiplex broadcast when it is OFF is stored, and this is displayed first. In addition, since FM multiplex broadcasting is almost updated after a few minutes,
If 3 minutes have passed from turning the power off to turning it on, RA
The initial screen is displayed without displaying the old information stored in M (17). This makes it possible to prevent the novelty of information from being impaired.

[0018]

In the voice mode whose main purpose is voice, the display information in the voice mode is not always the information that should always be displayed. Therefore, a small FM, such as a car, which cannot display information related to many modes at once
In the multiplex broadcast receiving device, in order to effectively use the display device, the display device can be effectively used by displaying the information of the FM multiplex broadcast even in the audio mode.

When switching to the FM multiplex display, the RAM can immediately display the information of the FM multiplex broadcast without waiting for the reception of a new FM multiplex broadcast.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a display device and an operation unit according to an embodiment.

FIG. 3 is a flowchart showing the main operation of the control circuit of the embodiment.

FIG. 4 is a detailed flowchart of the FM multiplex processing shown in FIG.

5 is a detailed flowchart of the TAPE process shown in FIG.

6 is a detailed flowchart of the processing of AM / FM shown in FIG.

FIG. 7 is a diagram showing an initial screen in FM multiplex mode.

FIG. 8 is a diagram showing a display screen of FM multiplex information.

FIG. 9 is a diagram showing a screen in a TAPE mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 FM multiplex broadcast receiving device 2 FW receiving circuit 11 Multiplex signal detecting circuit 14 Operation part 15 Control circuit 16 ROM 17 RAM 18 Display device 21 Speaker 23 Vehicle battery 24 POWER switch 25 Vehicle ignition switch

Claims (1)

[Claims] 1. An FM receiving circuit for receiving an FM broadcast, a multiplex signal detecting circuit for detecting first display information multiplexed in the FM broadcast by the FM receiving circuit, and irrelevant to the first display information. Audio output means for outputting audio information, and a control circuit for outputting second display information related to the audio output means,
An FM multiplex broadcast receiving device having a display device for displaying the first or second display information and a key for operating an output start of the audio information, comprising storage means for storing the first display information, The control circuit displays the second display information for a predetermined time based on the operation of the key, and then displays the first display information stored in the storage means. apparatus.