JPH02165716A - On-vehicle electronic tuning receiver - Google Patents

Abstract

PURPOSE:To immediately obtain a comfortable reception state even when the reception state deteriorates by automatically switching an electric filed strength by which an automatic tracking function is operated corresponding to the reception state. CONSTITUTION:When reception electric field strength goes less than a constant level, the electric field strength by which the automatic tracking function is operated is switched to a low side when no intensive broadcast station exists even by switching a frequency, and furthermore, it is awaited until the reception electric field strength is lowered, and the automatic tracking function is operated again. Also, when the reception electric field strength is kept at a level exceeding a prescribed level for constant time, the electric field strength level by which the automatic tracking function is operated is switched to a higher level, and the automatic tracking function is operated before the reception state deteriorates. In such a manner, it is possible to always obtain a satisfactory reception state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention specifically relates to an automatic tracking function of an RDS-compatible in-vehicle electronic tuning receiver.

(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, and will be briefly explained below.

FIG. 3 shows the spectra of the FM stereo signal, RDS, and ART signals.

As shown in Figure 3(a), the FM signal consists of a monaural audio signal (L + R) and a signal for stereo audio (
L-R), stereo pilot signal (19kHz)
Consisting of Also, the traffic information identification (ARI) signal is 57k.
Hz subcarrier as a low frequency traffic information area identification signal (B
K) is a signal amplitude-modulated with an identification signal (DK) during traffic information broadcast.

As shown in FIG. 3(b), the RDS signal is distributed at a low level near the 57 kHz subcarrier and is orthogonal to the carrier of the ARI signal.

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

As shown in (b), the transmission rate of RDS data is 1.1875
bits per second. Figure 4 (C) is a differential encoded version of this signal.
This signal modulates the subcarrier (57k) Iz) with carrier suppression amplitude modulation [Figure 4(f)), and converts this double sideband (DSB) signal into an audio signal. Multiplex and transmit.

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), the broadcasting station name (PS), and the same name for up to 25 stations, as shown in Figure 7. There is a frequency list (AF) of broadcast stations broadcasting programs, a traffic information station identification signal (TP), a traffic information program broadcasting identification signal (TA), etc.

By using these transmission data, many functions such as automatic tuning of the best receiving station for the same program (automatic tracking function), traffic information identification, broadcast station display, etc. can be realized.

Among these, the automatic tracking function is considered to be realized in a first-order manner using an AP multiplied signal and a 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. When the received electric field strength falls below a certain level, the system switches to another broadcasting station from the AF double signal readout frequency list, checks its electrolytic strength, and selects the broadcasting station whose electric field intensity is above a certain level. Furthermore, a method has been proposed in which the newly received program identification code (PI) is compared with the PI stored in memory to confirm whether the program received according to the frequency list is correct.

(Problem to be solved by the invention) However, if there is no strong broadcasting station even if you switch the frequency when the received electrolytic strength falls below a certain level, this method will repeatedly switch the frequency at the same electrolytic level. . In order to suppress noise when switching one frequency, muting is applied repeatedly, which has the disadvantage of causing sound interruptions and making the sound unnatural.

An object of the present invention is to eliminate the drawbacks of the conventional technology and provide two levels of electric field strength at which the automatic tracking function operates.

To provide a vehicle-mounted electronic tuning receiver that automatically switches depending on the reception state.

(Means for Solving the Problems) The in-vehicle electronic tuning receiver of the present invention utilizes RDS data to further transmit radio waves when the received electric field strength decreases as the car moves while receiving signals while driving. It has an automatic tracking function that automatically selects the same program station with a strong intensity, and has two levels of electric field strength at which the automatic tracking function operates, and a mechanism that automatically switches between them.

(Function) With the above configuration, when the received electric field strength falls below a certain level and there is no strong broadcasting station even if the frequency is switched, the electric field strength level at which the automatic tracking function operates is switched to a lower one, and further Wait for the received electric field strength to decrease, then activate the automatic tracking function again, and if the received electric field strength exceeds a certain level for a certain period of time, switch the electric field strength level at which the automatic tracking function operates to a higher one. , the automatic tracking function will operate before the reception condition becomes too bad.

(Example) An example of the present invention will be described based on FIGS. 1 and 2. FIG. 1 shows the overall configuration of an RDS-compatible in-vehicle electronic tuning receiver according to the present invention. In the same figure,
1 is a 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, 5
6 is an RDS decoder that demodulates the RDS modulation signal extracted from the FM demodulation output and regenerates the clock, and 6 is the demodulated R
The microcomputer part 7 performs group synchronization of DS data, error detection, and correction, and 7 decodes and stores group-synchronized RDS data, displays data, controls P[ and L of the FM receiver, and monitors received field strength. This is the main microcomputer unit that performs key human power processing, RDS data processing, and hardware control. 8 is a display section, and 9 is a keyboard.

Next, a feature of the present invention in which the electric field strength level at which the automatic tracking function operates is automatically switched according to the reception state will be explained.

When a key to activate the automatic tracking function is pressed on the keyboard 9 while receiving an RDS station, the main microcomputer section 7 accepts this key input and
A program as shown in FIG. 2 is run.

FIG. 2 is a flow chart for explaining the operation of the present invention.

In the same figure, V? I is the electric field strength level at which the automatic tracking function operates, and vo is the received electric field strength.

V Yu. is the lower electric field strength level stored in advance, and ■! , is a pre-stored higher electric field strength level.

Set Vvm to the lower level. Next, start timers 1 and 2, measure the received field strength, and compare them. If the received field strength is low, set timer 2 to a constant level. Automatic channel selection is performed after checking that this state continues for a certain amount of time. After that, the received electric field strength is monitored again.

Next, if the received field strength is higher, check that this state continues for a certain period of time with timer 1, and then
After switching to a higher level, the received field strength is monitored again, and when the received field strength becomes low again, the same operation as above is repeated.

(Effects of the Invention) According to the present invention, the electric field strength level at which the automatic tracking function operates is automatically switched depending on the reception condition. , the automatic tracking function works and you can immediately obtain comfortable reception conditions. In addition, in areas with weak radio waves, the automatic tracking function reduces the frequency of audio interruptions and eliminates unnatural sound, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a vehicle-mounted electronic tuning receiver to which the present invention is applied, FIG. 2 is a flowchart for explaining the operation in an embodiment of the present invention, and FIG. 3 is a block diagram showing an example of an FM stereo signal and an RDS , AR ■ signal spectrum, Figure 4 is the RDS signal waveform diagram, Figure 5 is the RDS data structure diagram,
Figure 6 is the RDS data format, Figure 7 is the RDS
FIG. 1... Front end section, 2... Intermediate frequency amplification section, 3... FM stereo signal demodulation section, 4
...Low frequency amplification section, 5 ...RDS decoder,
6...Microcomputer, 7...Main microcomputer,
8...Display section, 9...Keyboard. Patent applicant Matsushita Electric Industrial Co., Ltd. (57kHz) Figure 2 vso: (4(Ill'!411!1zA-)1/
Figure 4 Figure 3 (a) (b) Mouse 4 length (kHz) Kasumi 5 Figure 6 Section P

Claims (1)

[Claims] In-vehicle use with an automatic tracking function that uses RDS data to automatically select the same program station with a stronger signal when receiving signals while driving in a car and the received field strength decreases as you move. In an electronically tuned receiver,
An in-vehicle electronic tuning receiver having two electric field strength levels at which the automatic tracking function operates, and having a function of automatically switching between the electric field strength levels.