JP2010232831A - Rds receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To circumvent the generation of unneeded switching noise due to the repetition of AF station check, even though an AF station list is short and a reception environment is not changed by much, and to smoothly switch broadcasting to an AF station, when a reception state is deteriorated. <P>SOLUTION: An RDS (Radio Data System) receiver is provided with an automatic tracking function of selecting a broadcast station broadcasting the same program as a program which is viewed during movement; determining the reception state; and switching reception to the broadcast station broadcasting the same program, when the reception state determined there is better than the reception state of the program being viewed. The RDS receiver includes a vehicle speed detector 25 for detecting the moving speed of a mobile object, and a control part 24 for varying the inhibition time of reception switching to the broadcast station of the better reception state, corresponding to the moving speed detected by the vehicle speed detector 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention selects a broadcasting station that is broadcasting the same program as the program that is being viewed while moving, and determines the reception state. Next, the determined reception state is better than the reception state of the program that is being viewed. The present invention relates to an RDS receiver having an automatic tracking function for switching reception to a broadcasting station that is broadcasting the same program.

In particular, RDS (Radio Data System) receivers, which are popular in Europe, are broadcasting stations that are broadcasting the same program as the program being viewed based on the AF list and PI code in the data included in the broadcast wave. AF station) is selected and the reception state is determined. If the determined reception state is better than the reception state of the program being viewed, an automatic follow-up function (hereinafter, referred to as “switching reception” to the broadcasting station that is broadcasting the same program) AF check function).
Here, the AF list is an alternative frequency list, and the PI code is a broadcast station code.

  By the way, since there is a trade-off relationship between the sound interruption generated by the AF check function and the noise generated at the time of switching and the smooth broadcast switching to the AF station when the reception state deteriorates, whichever has been prioritized. Depending on whether or not, switching methods (1) to (4) listed below have been studied.

(1) The reception status of the AF station is always monitored at regular intervals, the reception status of all the AF stations listed in the AF list is determined, and the AF station with the best reception status is compared with the reception status currently being viewed. If it is OK, switch to the AF station.
(2) The reception state of the receiving station being viewed is monitored, and when the reception state deteriorates, the reception states of all the AF stations are confirmed, and the reception state of the AF station with the best reception state is higher than that of the receiving station being viewed. If so, switch to that AF station.
(3) Regardless of the receiving state of the receiving station, periodically select one AF station and check the receiving state. If the confirmed receiving state of the AF station is better than the receiving station being viewed, switch to that AF station. . However, it does not matter whether the AF station to be selected is determined randomly.
(4) The reception state of the receiving station being viewed is monitored, and when the reception state deteriorates, one AF station is selected and the reception state is confirmed, and the confirmed reception state of the AF station is higher than the receiving station being viewed. If it is OK, switch to the AF station. However, in this case as well, it does not matter whether the AF station to be selected is random.

  The above (1) and (2) are methods that prioritize the reliable selection of the station with the best reception state in the AF list by checking all the reception states of the broadcasting stations described in the AF list. (Hereinafter referred to as “reception state priority method” for convenience of explanation). On the other hand, (3) and (4) are methods that prioritize minimizing switching noise and sound interruption due to AF check (hereinafter referred to as “sound interruption avoidance priority method” for convenience of explanation).

Using the reception status priority method described above makes sound cuts less likely to occur, but only when driving at low speeds, the AF check is repeated and the sound cuts off frequently even though the reception status has not changed much. May occur.
In order to solve this, for example, in Patent Document 1, in the “reception state priority method”, when confirming the reception states of all AF stations, the confirmation time interval is changed according to the vehicle speed, An automatic tracking method of a radio receiver that can reduce unnecessary reception switching is disclosed. Patent Document 2 discloses an AF check method for acquiring the reception statuses of all AF stations with one AF check. The AF list check period is variable depending on the vehicle speed, and as a result, all AF stations are being checked. A method is disclosed in which the check interval is variable depending on the vehicle speed. Patent Document 2 further discloses that the PI code check interval is made variable according to the vehicle speed by using the PI code check interval determined according to the vehicle speed.

Japanese Patent Laid-Open No. 3-148923 Japanese Patent Laid-Open No. 11-163751

However, the method disclosed in Patent Document 1 described above cannot be applied to the sound interruption avoidance priority method in which AF stations are confirmed one by one, and thus the above-described problem cannot be solved.
Since the technique disclosed in Patent Document 1 is originally based on the reception state priority method, it takes a lot of time to check the reception states of all AF stations. Therefore, especially during high-speed driving, there is a possibility of passing through a place where the reception state is bad while checking the reception state of the AF station. If the reception state has already been recovered, reception switching is not performed Better. In addition, there is a high possibility that a lot of noise will be emitted from the speaker due to delay in reception switching to the AF station. In addition, since no waiting time is set when checking the PI code of each AF station, a long mute period occurs for PI code checking when there are multiple broadcasting stations with different PI codes in multiple AF lists. However, it may lead to frequent sound interruptions.

On the other hand, according to the technique disclosed in Patent Document 2, the reception status of all AF stations is monitored by changing the time interval of the AF check based on the vehicle speed even during the reception status check of all AF stations. However, the above-mentioned problem at high speed is relatively less likely to occur, but the point that all AF stations are still checked remains the same. Therefore, the check takes some time.
In addition, by setting a waiting time that is linked to the vehicle speed even when the same broadcast station is determined in the PI code check, the possibility of frequent switching in a short time when PI code check is reduced. However, the waiting time for the PI code check becomes longer due to the setting of the waiting time.

  The present invention has been made to solve the above-described problems, and in particular, avoids unnecessary switching noise caused by repeating the AF station check even though the AF station list is small and the reception environment does not change much. An object of the present invention is to provide an RDS receiver that realizes smooth broadcast switching to an AF station when the reception state deteriorates.

  In order to solve the above-described problems, the present invention selects a broadcasting station that is broadcasting the same program as the program that is being viewed while moving, determines the reception state, and the determined reception state is the program that is being viewed. An RDS receiver having an automatic follow-up function for switching reception to a broadcasting station that is broadcasting the same program if it is better than a reception state, a vehicle speed detector for detecting a moving speed of a moving body, and the vehicle speed And a control unit that varies the prohibition time of the reception switching to the broadcasting station having a good reception state according to the moving speed detected by the detector.

  According to the present invention, it is possible to avoid unnecessary switching noise caused by repeating the AF station check even when the AF station list is small and the reception environment does not change so much. It is possible to provide an RDS receiver that realizes effective broadcast switching.

It is a block diagram which shows the internal structure of the RDS receiver which concerns on Embodiment 1 of this invention. 5 is a flowchart showing an operation of the RDS receiver according to the first embodiment of the present invention. It is a figure which shows an example of the AF station list which the RDS receiver which concerns on Embodiment 1 of this invention received from the broadcasting station.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing an internal configuration of the RDS receiver according to Embodiment 1 of the present invention.
As shown in FIG. 1, the RDS receiver according to Embodiment 1 of the present invention includes an antenna 11, an RF amplifier 12, a mixing circuit 13, an intermediate frequency (IF) amplifier 14, an FM demodulator 15, Stereo decoder 16, mute circuit 17, power amplifier 18, speaker 19, PLL (Phase Locked Loop) circuit 20, field intensity / noise detector 21, RDS demodulator 22 as an RDS demodulator circuit, RDS A decoder 23 and a control unit 24 are included.

  The RDS receiver described above is attached to a vehicle as a moving body, and a vehicle speed detector 25 such as a vehicle speed sensor for converting the vehicle speed into an electric signal is attached to the vehicle at an arbitrary place of the vehicle. It shall be.

In FIG. 1, an RF band signal received by the antenna 11 is amplified by an RF amplifier 12 and input to a mixing circuit 13. In addition, the local oscillation frequency signal generated by the PLL circuit 20 is input to the mixing circuit 13, where it is converted into an IF band frequency signal by mixing with the previously received RF band signal.
The IF band signal generated by the mixing circuit 13 is amplified by the IF amplifier 14 and supplied to the FM demodulator 15 and the electric field strength / noise detector 21. The received electric field strength (RSSI value: Received Signal Strength Indicator) and noise detected by the electric field strength / noise detector 21 are supplied to the control unit 24.

The FM demodulator 15 demodulates the output of the IF amplifier 14 to extract an MPX (Multiplex) signal and supplies it to the stereo decoder 16 and the RDS demodulator 22. The stereo decoder 16 extracts the L-channel and R-channel audio signals from the MPX signal and supplies them to the mute circuit 17, and the RDS demodulator 22 extracts the RDS data from the MPX signals and supplies it to the RDS decoder 23.
The mute circuit 17 performs a mute process on the audio signal output by the stereo decoder 16 at a timing specified by the control unit 24, supplies the mute process to the power amplifier 18, and amplifies the power for driving the speaker 19 by the power amplifier 18. Generate.

  The PLL circuit 20 generates a frequency signal designated by the control unit 24 by a VCO (Voltage Controlled Oscillator) built in the PLL circuit 20 and controls the mixing circuit 13.

  As will be described later, the control unit 24 has a function of making the reception switching prohibition time to a broadcasting station with a good reception state variable according to the moving speed of the vehicle. As shown in the functional development, the reception state determination unit 241, the AF check execution control unit 242, the AF check prohibition time setting unit 243, and the vehicle speed determination unit 244 are included.

The reception state determination unit 241 determines the reception state by comparing the signal output from the electric field strength / noise detector 21 with a threshold value, and controls the AF check execution control unit 242 to execute the AF check.
The AF check execution control unit 242 determines a reception state by selecting a broadcasting station that is broadcasting the same program as the program being viewed while the vehicle is traveling, and the determined reception state is higher than the reception state of the program being viewed. If it is good, it is a functional block that executes an automatic follow-up function that switches reception to the broadcasting station that is broadcasting the same program.

  The AF check prohibition time setting unit 243 changes the prohibition time of reception switching to a broadcasting station having a good reception state according to the moving speed of the vehicle, and controls the AF function execution by the AF check execution control unit 242. For this reason, the AF check prohibition time setting unit 243 is a functional block that acquires a vehicle speed pulse from the vehicle speed detector 25 attached to the vehicle and sets the reception switching prohibition time based on the vehicle speed information determined by the vehicle speed determination unit 244.

FIG. 2 is a flowchart showing the operation of the RDS receiver according to Embodiment 1 of the present invention.
Hereinafter, the operation of the RDS receiver according to Embodiment 1 of the present invention will be described in detail with reference to the flowchart shown in FIG.

In the flowchart of FIG. 2, the control unit 24 (AF check execution control unit 242) first sets a value “1” to the counter x set by the program (step ST201).
On the other hand, the reception state determination unit 241 constantly monitors the reception state from the output value of the electric field intensity / noise detector 21 (step ST202).

  Here, for example, when the reception environment deteriorates compared to a predetermined RSSI value (threshold) (step ST202 “NO”), the reception state determination unit 241 activates the AF check prohibited time setting unit 243, The received AF check prohibition time setting unit 243 acquires vehicle speed information from the vehicle speed detector 25 via the vehicle speed determination unit 244 (step ST203), sets the AF check prohibition time T according to the acquired vehicle speed information, and performs AF. The check execution control unit 242 is handed over (step ST204).

Next, the AF check execution control unit 242 determines whether a time equal to or longer than the AF check prohibition time T has elapsed since the previous AF check (step ST205).
Here, when it is determined that the time longer than the AF check prohibition time T has not yet passed (step ST205 “NO”), the process returns to step ST202, and the AF check execution control unit 242 deteriorates the reception state again. Wait until you do.

  By controlling in this way, within the range of the AF check prohibition time T, even if the reception state deteriorates, switching is not performed to check the reception state of the AF station, and a short period during low-speed traveling AF check execution is suppressed. At the same time, the real-time property of reception status monitoring is maintained.

When it is determined in the AF check time determination process in step ST205 that the time equal to or longer than the AF check prohibition time T has elapsed (step ST205 “YES”), the AF check execution control unit 242 transmits from the broadcast station. One AF station is selected from the AF station list, and the reception state determination unit 241 starts checking the reception state of AF (x). FIG. 3 illustrates AF lists AF (1) to AF (N) received from a broadcasting station.
Specifically, the AF check execution control unit 242 performs mute processing before switching to the AF station by controlling the mute circuit 17 to prevent the generation of abnormal noise such as noise generated when the AF station is switched (step ST206). ), The AF station is received (step ST207), and it is determined whether or not the reception state of AF (x) is good (step ST208).

  Here, the reception state determination unit 241 determines the reception state based on RSSI of the AF station, and if the RSSI value is equal to or less than the threshold value, determines that the reception state is not good and notifies the AF check execution control unit 242 ( In step ST208 “NO”), the AF check execution control unit 242 sets the counter x to be updated by +1 and checks the next AF station (step ST210). Here, in step ST210, when x = N, x = 1 is set.

Subsequently, the AF check execution control unit 242 performs reception setting before receiving the AF check (immediately before starting mute) (step ST211), controls the mute circuit 17 to release mute (step ST212), and then performs step ST202. Return to the reception status determination process.
If it is determined that the reception state is good in the AF (x) reception state determination process in step ST208 ("YES" in step ST208), the AF check execution control unit 242 further refers to the PI code and transmits the same broadcast station. Whether or not (step ST209).

  Here, if it is determined that the PI code is different (step ST209 “NO”), the value of the counter x is updated by +1 and the next AF station is checked as in the case where the reception state of AF (x) is not good. (Step ST210). Then, reception is set to the receiving station before the AF check is started (immediately before the mute is started) (step ST211), the mute circuit 17 is controlled to cancel the mute (step ST212), and the process returns to the reception state determination process of step ST202.

  On the other hand, when it is determined that the PI code is the same and the same broadcasting station (step ST209 “YES”), the AF check execution control unit 242 sets the receiving station as the AF station currently being checked (step ST213). The mute circuit 17 is controlled to cancel the mute (step ST214). Subsequently, the AF check execution control unit 242 sets the AF station number to be checked at the next reception deterioration in the internal counter x (step ST215), and returns to the reception state determination process of step ST202.

  As described above, when the reception state check and switching process of one AF station shown in step ST206 and after are always returned to the reception state determination process of step ST202 after the process is completed, the reception state of the receiving station is once deteriorated. In this way, control is implemented so that the reception status of all AF stations is not checked. As a result, the time required for one AF check is shortened, and switching to the AF station can be performed at an appropriate timing.

  According to the RDS receiver according to Embodiment 1 of the present invention described above, the control unit 24 is prohibited from switching reception to a broadcasting station having a good reception state according to the moving speed detected by the vehicle speed detector 25. The reception state of the broadcasting station being watched is determined in detail, and if the reception state is determined to be not good, the broadcast with the good reception state according to the vehicle speed detected by the vehicle speed detector 25 is determined. Set the reception switching prohibition time T to the station, start muting on the condition that the reception switching prohibition time has passed since the previous reception determination, and switch to reception, and confirm that it is the same broadcast station as before switching Unnecessary switching noise occurs especially when the AF station check is repeated even though the AF station list is small and the reception environment does not change much. Avoiding, it is possible to realize smooth broadcast switching to AF station at the time of reception condition deterioration.

  In addition, according to the RDS receiver according to the first embodiment described above, only the case where it is applied to a vehicle as a moving body has been described. However, the present invention is not limited to a vehicle and can be similarly applied to a moving body in general. is there.

1 may be realized entirely by software, or at least a part thereof may be realized by hardware.
For example, the data processing in which the control unit 24 changes the reception switching prohibition time to a broadcasting station having a good reception state according to the moving speed detected by the vehicle speed detector 25 is performed on a computer by one or a plurality of programs. Or at least a part of which may be realized by hardware.

  11 antenna, 12 RF amplifier, 13 mixing circuit, 14 IF amplifier, 15 FM demodulator, 16 stereo decoder, 17 mute circuit, 18 power amplifier, 19 speaker, 20 PLL circuit, 21 electric field intensity / noise detector, 22 RDS Modulator (RDS demodulation circuit), 23 RDS decoder, 24 control unit, 25 vehicle speed detector, 241 reception state determination unit, 242 AF check execution control unit, 243 AF check prohibition time setting unit, 244 vehicle speed determination unit.

Claims (2)

A broadcast station that is broadcasting the same program as the program being viewed while moving is selected to determine the reception state. If the determined reception state is better than the reception state of the program being viewed, the same program is selected. An RDS receiver having an automatic tracking function for switching reception to a broadcasting station,
A vehicle speed detector for detecting the moving speed of the moving body;
A control unit that varies the prohibition time of reception switching to a broadcasting station in which the reception state is good according to the moving speed detected by the vehicle speed detector;
An RDS receiver comprising: The controller is
Determine the reception status of the broadcasting station you are watching,
When it is determined that the reception state is not good, a reception switching prohibition time to a broadcasting station in a good reception state is set according to the vehicle speed detected by the vehicle speed detector,
The mute is started on the condition that the reception switching prohibition time has elapsed since the previous reception determination, the reception is switched, and the mute is canceled after confirming that the broadcasting station is the same as before the switching. The RDS receiver according to claim 1.

Images