JPH02165717A - On-vehicle electronic tuning receiver - Google Patents

Abstract

PURPOSE:To shorten a time required for automatic tracking by performing IF count after searching the same program station with the most intensive wave in reception electric field strength at the time of performing automatic channel selection. CONSTITUTION:When the reception electric field strength is lowered according to the movement of a vehicle in the case of reception while driving with an automobile, a frequency list AF signal is read out first, and the reception is performed by switching a broadcast station to another one from a frequency list (at this time, no IF count is performed). Next, the reception electric field strength is checked. After the station with the most intensive reception electric field strength is searched by repeating such operation, the IF count is performed, and it is confirmed whether or not the reception is performed with a correct frequency. Furthermore, it is confirmed whether or not the station is the same program station by checking a program identification PI code. In such a manner, the automatic tracking can be accelerated.

Description

[Detailed description of the invention] (Industrial application field) The present invention is an RDS-compatible in-vehicle electronic tuning receiver.

Specifically, it relates to its automatic tracking function.

(Prior Art) RDS (Radio Data System) is a system that multiplexes and transmits digital data for channel selection and the like on FM broadcast signals.

FIG. 3 shows the spectra of the FM stereo signal, RDS, and ARIR signal. As shown in Figure 3(a), FM
The signal consists of a monaural audio signal (L + R), a signal for making stereo audio (L - R), and a stereo pilot signal (19kHz).

The traffic information identification (ARI) signal is a signal obtained by amplitude modulating the subcarrier of 57kl(z) with a low frequency traffic information area identification signal (BK) and an identification signal during traffic information broadcasting (DK).

As shown in Figure 3(b), the RDS signal has a frequency of 57kHz.
It is distributed at a low level near the subcarrier of , and has an orthogonal relationship with the AR multiplier signal carrier.

FIG. 4 is an RDS signal waveform diagram, and FIG. 4(a).

As shown in (b), the transmission speed of RDS data is 1.
1875 bits/second. This signal is differentially encoded as shown in Figure 4 (Q).

The 1.1875kHz clock is converted into a two-phase P S K (P
This signal modulates the subcarrier (57kHz) (Figure 4(d)).
This double sideband (DSB) signal is subjected to carrier suppression amplitude modulation (FIG. 4(f)), and is multiplexed with the audio signal and transmitted.

The data structure of RDS is shown in Figure 5.The RDS data is 1
It consists of groups of 04 bits, and one group consists of 4 bits.
It consists of two blocks. One block consists of 26 bits, of which 16 bits are information words and the remaining 10 bits are check words.

The RDS data format is shown in Figure 6, and the information sent includes the broadcasting station identification code (PI), broadcasting station name (PS), and up to 25 stations, as shown in Figure 7. There is a frequency list (AP) of broadcast stations broadcasting the same program, a traffic information station identification signal (TP), a traffic information program broadcasting identification signal (TA), etc. using these transmitted data.

Automatic tuning of the best receiving station for the same program (automatic tracking function)
, traffic information identification, broadcast station name display, and many other functions can be realized.

Among these, the automatic tracking function is considered to be realized as follows using the AF multiplied signal and the PI multiplied signal.

That is, when a certain broadcasting station is received, the AF double signal and PI double signal are stored in the memory. If the received electric field strength is below a certain level, read out the AF multiplied signal, switch to another broadcast station from the frequency list and receive it, check the electric field strength and select the broadcast station with electric field strength above the certain level, and then select the broadcast station with the electric field strength above the certain level. A conceivable method to check whether the program received according to the above is correct is to compare the newly received program identification code (PI) with the PI stored in the memory.

(Problems to be Solved by the Invention) However, during automatic channel selection, it is necessary to mute the system in order to suppress noise during frequency switching, which has the disadvantage of causing sound interruptions and making the sound unnatural.

The purpose of the present invention is to eliminate the drawbacks of the conventional system, read out the AF double signal so that automatic tuning can be performed in as short a time as possible, and receive the signal at the correct frequency when switching to another broadcasting station from the frequency list. IF to check whether it is completed
To provide an on-vehicle electronic tuning receiver that omits counting and performs IF counting after searching for the station with the strongest received electric field strength.

(Means for solving the problem of lllli!) The in-vehicle electronic tuning receiver of the present invention is capable of detecting RDS when the received electric field strength decreases as the car moves.
In-vehicle electronic tuning receivers that have an automatic tracking function that uses data to automatically select the same program station with the strongest radio waves, search for the same program station with the strongest radio wave based on the received field strength when automatically tuning. After that, the IF count is performed.

(Function) The present invention is applicable to cases where the received electric field strength decreases as the vehicle moves while receiving data while driving.

First, read the AF double signal, switch to another broadcast station from the frequency list, and receive it (at this time.

(No IF count) First, check the received electric field strength. After repeating this process to find the station with the strongest received field strength, perform an IF count to confirm that you are receiving on the correct frequency. Then, the PI code is further checked to confirm whether it is the same program station.

(Example) An example of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a block diagram showing the overall configuration of an RDS-compatible in-vehicle electronic tuning receiver according to the present invention.

In the figure, 1 is the front end section of the receiver, 2 is an intermediate frequency amplification section, 3 is an FM stereo signal demodulation section, 4 is a low frequency amplification section, and 5 is a demodulator of the RDS modulated signal extracted from the FM demodulation output. , a part that regenerates the clock, 6 a microcomputer part that performs group synchronization and error detection and correction of demodulated RDS data, 7 a microcomputer part that decodes and stores the group synchronized RDS data, and displays the data and PLL of the FM receiver. This is the main microcomputer part that performs control, monitoring of received field strength, key human power processing, RDS data processing, and hardware control. 8 is a display section, and 9 is a keyboard.

Next, the automatic tracking function, which is a feature of the present invention, will be explained.

FIG. 2 is a flowchart showing the algorithm of the automatic tracking function.

This algorithm starts when the received electric field strength drops to a level that allows the automatic tracking function to operate.

First, read out the already stored AF multiplication signal.

Switch the reception frequency to one in the frequency list. 6. Next, perform a PLL lock check and wait until the PLL locks. 0. Next, measure the received electric field strength. Then, the received electric field strength is measured for all the stations in one frequency list, and the station is switched to the strongest station among them.

After this, IF count and PI check are performed.

(Effects of the Invention) According to the present invention, since IF counting is omitted when switching the receiving frequency to one in the frequency list, the time required for automatic tracking can be shortened. , its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an in-vehicle electronic tuning receiver according to an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the algorithm, and FIG. 3 is a spectrum of an FM stereo signal, RDS, and ARI signals, Figure 4 is an RDS signal waveform diagram, Figure 5 is an RDS data structure diagram, and Figure 6 is an RDS signal waveform diagram.
DS Data Format FIG. 7 is a diagram showing information sent by RDS. 1...Front end section, 2...Intermediate frequency amplification section, 3...FM stereo signal demodulation section. 4...Low frequency amplification section, 5...RI) S decoder. 6...Microcomputer, 7...Main microcomputer, 8...
・Display section, 9...Keyboard. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 2 TP Figure 3 (a) (b) Layer to skin yield (k) - 1z) Figure 5 Figure 6 (57kHz) Figure 4 Figure 7

Claims (1)

[Claims] In-vehicle electronic tuning reception that has an automatic tracking function that uses RDS data to automatically select the same program station with a stronger signal when receiving while driving in a car and the received field strength decreases as you move. An on-vehicle electronic tuning receiver is characterized in that when automatically selecting a station, it searches for the same program station with the strongest received field strength and then performs an IF count.