JPH0730376A - Radio receiver - Google Patents

Abstract

PURPOSE:To eliminate a frequency break of a broadcast being received due to contiguous channel interference by providing an electric field intensity measuring means and a means which measures electric field intensity in a measurement band narrower than the measurement band of the electric field intensity. CONSTITUTION:A control means 4 has a means which stores the transmission frequency of an identical series station demodulated by a data demodulating means 3 in a series station storage means 5. Then a transmission frequency which is larger in the electric field intensity, outputted by a tuning means 1, than a specific value and less in narrow band electric field intensity than the specific value among transmission frequencies is marked and stored in the means 5 so that it can be discriminated; and the specification of the marked transmission frequency to the means 1 is suppressed by a means (never tuned). Even if there is a broadcast channel where a measurement result indicating electric field intensity larger than actual intensity is obtained owing to contiguous channel interference although the actual electric field intensity is weak, the reproduction of the broadcasting is never repeated more than twice, so a frequency break of the broadcast being received is eliminated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to radio receivers. More specifically, the present invention relates to NF (N) in RDS (Radio data system) operated in Europe.
Regarding radio receivers that support etwork follow).

The present invention is particularly applicable to, but not limited to, a radio receiver mounted on a vehicle.

[0003]

2. Description of the Related Art In Europe, RDS is operated, and a radio receiver corresponding to NF in RDS is known. In this type of radio receiver, a circuit for demodulating a digital broadcast, which is frequency-multiplexed with an audio broadcast, is added, and is intermittent to a broadcasting station of the same series broadcast by the digital broadcast. Tuning control is performed, and the reception frequency is automatically changed to the affiliated station determined to be able to receive better.

FIG. 7 is a flow chart for explaining the conventional tuning control, that is, NF control. In addition,
The radio receiver in which the control is executed, in addition to the circuit for demodulating the digital broadcast, means for measuring the electric field strength near the tuning frequency, and the AF (Alternative Frequency) list broadcast by the digital broadcast, that is, A means for storing a list of transmission frequencies of affiliated stations is also added. Then, it is assumed that the broadcast AF list is already stored separately.

The control is intermittently executed at appropriate intervals. In step H100, the reception frequency is changed to the affiliated station in the stored AF list. In the reception frequency change, if a plurality of transmission frequencies of affiliated stations are stored in the AF list, the transmission frequencies are cyclically applied every time the control is executed.

In step H101, the electric field strength after the change of the reception frequency is measured and compared with the electric field strength before the change. If the electric field strength is stronger, control transfers to step H102. On the other hand, if the electric field strength becomes too weak, the control shifts to step H104, where the reception frequency is returned to the state before the change,
The control ends.

In step H102, a PI (Program Identification) code broadcast by the digital broadcasting after the reception frequency change, that is, a code indicating a series of broadcasting stations is confirmed. If the PI code received and demodulated after the change matches the PI code received and demodulated before the change, the received frequency is not returned and the control ends.

On the other hand, if the coincidence of the PI code cannot be confirmed, the control shifts to step H104, and step H10
In 4, the reception frequency is returned to the value before the change, and the control ends.

[0009]

The electric field strength measurement band spans the entire frequency band assigned to the broadcast channel with which the radio receiver is tuned. In RDS, the intervals between broadcast channels are relatively narrow, and it is not uncommon for broadcast channels belonging to different streams to be adjacent to each other.

Therefore, in the electric field strength measurement,
Adjacent channel interference may occur. As is well known, the adjacent channel interference is caused by the lack of the adjacent channel selectivity in the receiver, the spread of the sideband of the transmitted wave, the variation of the transmitted frequency, and the like.

FIG. 8 is a diagram for explaining a problem in the conventional NF control. Now, assume that the NF-compatible radio receiver is installed in a vehicle, and the vehicle passes in the vicinity of broadcasting stations A1, A2, and B in order, as shown in FIG. Here, the broadcasting stations A1 and A2 are broadcasting stations of the same series, and the broadcasting station B is a broadcasting station of a different series. It is assumed that the listener has designated reception of the affiliated broadcast to which the broadcast stations A1 and A2 belong.

FIG. 2B shows the frequency characteristics of the transmission wave of each broadcasting station at the positions shown in FIGS. Same figure (c)
Shows the frequency characteristics of the transmission wave of each broadcasting station at the positions of (a) and (b) in FIG. (D) of the figure shows the frequency characteristics of the transmission wave of each broadcasting station at the positions of (a) and (c) of the figure.

In FIGS. 2 (b), 2 (c) and 2 (d), f _A1 , f
_A2, f _B, respectively, the transmission frequency of the broadcast station A1, A2, B. The broadcast channel of the broadcast station A1 and the broadcast channel of the broadcast station B are adjacent to each other.

At the positions of (a) and (a) in the figure, as shown in (b) of the figure, the electric field strength of the broadcasting station A1 is higher than that of the broadcasting station A2.
, Which is larger than the electric field strength of the above, and the reception frequency is set to f _A1 by the NF control. Then, the electric field strength of the broadcasting station A2 is repeatedly measured intermittently.

At positions (a) and (a) in the figure, as shown in (c) in the figure, the electric field strength of the broadcasting station A2 is higher than that of the broadcasting station A1.
, Which is larger than the electric field strength of the above, and the reception frequency is set to f _A2 by the NF control. Then, the electric field strength of the broadcasting station A1 is repeatedly measured intermittently.

At the positions of (a) and (c) in the figure, as shown in (d) of the figure, the electric field strength of the broadcasting station A2 is actually larger than the electric field strength of the broadcasting station A1. However, in the electric field strength measurement of the broadcasting station A1, adjacent channel interference occurs due to the spread of the sideband of the transmission wave of the broadcasting station B,
A measurement result indicating that the electric field strength of the broadcasting station A1 is larger than that of the broadcasting station A2 is obtained.

Therefore, the PI code collation at the reception frequency f _A1 is executed by the NF control. However, in reality, the electric field strength of the broadcasting station A1 is weak, the digital broadcasting cannot be demodulated, and the coincidence of the PI codes cannot be confirmed. Therefore, the reception frequency is returned to the broadcasting station A2 again.

According to the NF control, the PI code collation at the reception frequency f _A1 is repeatedly executed intermittently around (a) and (c) in FIG. Then, during the period when the reception frequency is in tune with the broadcasting station A1, the actual electric field strength of the broadcasting station A1 is weak, so that noise is reproduced from the radio receiver. (Hereinafter, this operation will be referred to as a mischange.) Incidentally, it is a fact that several hundred ms is required until it is determined whether the digital broadcast cannot be demodulated. . Therefore, it is naturally expected that the listener will notice the reproduced noise during the PI code matching period, that is, during the period when the reception frequency is in tune with the broadcasting station A1.

If such mischanges are repeated, the listener may feel that the broadcast being received is interrupted due to noise, which may cause discomfort.

A technical problem of the present invention is to pay attention to such a problem, and to prevent a radio receiver corresponding to NF in the RDS from continuously interrupting a broadcast being received due to adjacent channel interference.

[0021]

FIG. 1 is a block diagram for explaining the basic principle of the present invention. The radio receiver of the present invention receives a radio wave, tunes to a frequency designated by the control means 4, and outputs a detection signal and an electric field strength near the tuning frequency, and a detection means output by the tuning means 1. Audio reproduction means 2 for reproducing audio broadcast from a signal
A data demodulation means 3 for demodulating a digital broadcast from a detection signal output from the tuning means 1; and a transmission frequency of the same-series station broadcast by the digital broadcast demodulated by the data demodulation means 3 is intermittently adjusted by the tuning means. 1, and the control means 4 for investigating the electric field strength output from the tuning means 1.

In the radio receiver of the present invention having such a structure, the tuning means 1 has means for measuring the narrow band electric field strength near the tuning frequency. Also,
The affiliated station storage means 5 has a storage area for storing the transmission frequencies of the same affiliated station and a storage area for identifying the transmission frequencies in a distinguishable manner.

In the radio receiver of the present invention having such a structure, the control means 4 stores the transmission frequency of the same series station demodulated by the data demodulation means 3 in the affiliated station storage means 5. Among the transmission frequencies, those in which the electric field strength output by the tuning means 1 is a predetermined value or more and the narrow band electric field strength output by the tuning means 1 does not reach a predetermined value are marked in an identifiable manner. It has a means for storing it in the affiliated station storage means 5 and a means for suppressing the designation of the transmission frequency so marked in the tuning means 1.

[0024]

The radio receiver of the present invention has means for measuring the electric field strength and means for measuring the electric field strength in a measurement band narrower than the measurement band of the electric field strength. The latter measurement result is the narrow band electric field strength.

The measurement band of the narrow band electric field strength in the radio receiver of the present invention is separately determined by experiment or calculation in consideration of adjacent channel interference. More specifically, if it can be practically removed, sufficient adjacent channel interference is determined by on-site verification and calculation, and a frequency band that is not interfered by such adjacent channel interference is selected.

For example, if the frequency band of one broadcast channel is 100 KHz and the adjacent channel interference is 30 KHz, which is sufficient for practical use, the measurement band may be set to 70 KHz or less.

In the radio receiver of the present invention, if there is a broadcasting channel in which the actual electric field strength is weak but adjacent channel interference occurs, the electric field strength measurement result is affected by adjacent channel interference as in the conventional case. However, the narrow band electric field strength has a small value according to the actual electric field strength because the measurement band is narrow and the adjacent channel interference is not received as described above.

If there is such a transmission frequency in the transmission frequencies of the affiliated stations, adjacent channel interference may occur at the transmission frequency and a measurement result indicating a larger electric field strength than the actual one may be obtained. It is marked and stored so that it can be identified. Then, once the storage is performed,
Tuning to the frequency is suppressed. That is, it is never tuned to that frequency.

Therefore, even if there is a broadcast in which adjacent channel interference occurs at the transmission frequency of the affiliated station and a measurement result indicating a larger electric field strength than the actual one is obtained,
The reproduction of the broadcast is not repeated twice or more.

On the other hand, the reason why the broadcasting being received is intermittently interrupted due to the adjacent channel interference in the past is that the actual electric field strength is weak, but the adjacent channel interference occurs and the measurement result indicating the electric field strength larger than the actual one is obtained. There is a broadcast channel that will be lost, and its playback is repeated.

In response to the cause, in the radio receiver of the present invention, as described above, although the actual electric field strength is weak, adjacent channel interference occurs and a measurement result indicating a larger electric field strength than the actual one is obtained. Even if there is a broadcast channel that is lost, the reproduction of the broadcast is not repeated twice or more, so that the broadcast being received is not interrupted constantly.

[0032]

EXAMPLES Next, examples of how the radio receiver according to the present invention is actually embodied will be described. FIG. 2 is a block diagram showing a configuration example of a radio receiver suitable for the present invention.

<< Description of Configuration >>
The signal received by the antenna 10 is input to the tuner circuit 11. In the tuner circuit 11, the frequency-multiplexed audio broadcast signal 40 and digital broadcast signal 41 are separated, and these are output to the audio reproduction circuit 12 and the data demodulation circuit 15, respectively.

FIG. 3A shows the reception characteristic of the tuner circuit 11 for the audio broadcast signal 40. Also, FIG.
(b) shows the reception characteristics of the tuner circuit 11 with respect to the digital broadcast signal 41. In the figure, f _TUNE is a tuning frequency, that is, a reception frequency. As shown in FIG. 2, the reception frequency f _TUNE is output from the port 18.

In the audio reproduction circuit 12, the audio signal for driving the speaker 13 is demodulated from the audio broadcast signal 40 and output to the speaker 13. Then, the speaker 13 reproduces the audio broadcast.

At this time, if the mute control 45 output from the port 14 indicates the mute on, the speaker 13
Drive is suppressed. On the other hand, when the mute control 45 instructs the mute off, the speaker 13 is driven by the audio reproduction circuit 12 and the audio broadcast is reproduced.

In the data demodulation circuit 15, the broadcast data is demodulated from the digital broadcast signal 41, and the port 16
Is output to. The broadcast data includes a PI code and AF list.

In the tuner circuit 11, the electric field strength near the reception frequency f _TUNE is measured. Figure 3
(c) shows the frequency characteristic of the electric field strength measurement in the tuner circuit 11. As shown in FIG. 2, the measured electric field strength 42 is output to the A / D conversion circuit 17, converted into a digital value in the A / D conversion circuit 17, and output to the port 18.

Further, in the tuner circuit 11, it is judged whether or not there is a radio wave having a sufficient electric field strength in the vicinity of the reception frequency f _TUNE . FIG. 3D shows frequency characteristics of the radio wave presence / absence determination in the tuner circuit 11. As shown in FIG. 2, the IFD 43 that is the determination result is
Output to port 18.

The CPU 19 executes the control described later. The control procedure is stored in the ROM 20. R
In the AM 21, a data area required for control executed by the CPU 19, an area for storing an AF list, and a storage area for marking a transmission frequency in the AF list in a distinguishable manner are secured.

CPU 19, ROM 20, RAM 21, port
Data transmission / reception is performed between 14, 16 and 18 via the bus 30 to which they are connected. The mute control 45,
The reception frequency f _TUNE is sent to the CPU 19 via the ports 14 and 18.
Specified by. The digital value of the electric field strength, the IFD 43, and the broadcast data are input to the CPU 19 via the ports 14, 16 and 18.

The result of the listener operating the operation panel 23 is input to the CPU 19 via the port 22 and the bus 30.

<< Explanation of affiliate station storage means >>
.. FIG. 4 is a diagram showing an example of the storage structure of the AF list. The storage area is RA
Secured in M21. PI for one series
An area for storing a code, an area for storing transmission frequencies of affiliated stations, and an area for storing non-PI flags and different PI flags that correspond one-to-one to the transmission frequencies of these affiliated stations are secured.

The storage areas are reserved for N sets corresponding to the preset numbers 1 to N.

<< Description of Control Means for Storing Transmission Frequency of Affiliated Station >> The storage area is CP
It is updated under the control of U19. The breakdown of the update is (1)
These are update of different PI flag and non-PI flag by NF control described later, (2) registration of new transmission frequency, and (3) rearrangement of transmission frequency.

First, registration of a new transmission frequency will be described. Now, it is assumed that the listener operates the operation panel 23 to select the preset number 1. When the AF list is demodulated in the data demodulation circuit 15, the A
The F list is read out via the port 16 and temporarily stored in another storage area in the RAM 21. This will be referred to as a primary list.

Next, the transmission frequency registered in the primary list is compared with the transmission frequency registered in the preset number 1. If the transmission frequency registered in the primary list is already registered in preset number 1, the transmission frequency is discarded and deleted from the primary list.

On the other hand, the transmission frequency not registered in the preset number 1 is registered in the registration order next to the transmission frequency already registered in the preset number 1. Then, the transmission frequency is deleted from the primary list. At this time, the no-PI flag and the different PI flag corresponding to the transmission frequency are
It is initialized to 0.

However, among the transmission frequencies already registered in the preset number 1, if the different PI flag is set to 1, the registration order of these is the last and the registration is performed. So that there will be no missing numbers in the ranking,
Can be rearranged.

When registering a new transmission frequency, if the registered transmission frequency is full, the transmission frequency registered in the last registration order is discarded. If the transmission frequency in which the different PI flag is set to 1 is registered, the transmission frequency is discarded. Then, such control is performed until the primary list becomes empty. Even if another preset number is selected,
It is the same.

Next, rearrangement of transmission frequencies will be described. Now, the listener operates the operation panel 23,
Suppose you have selected preset number 1. Then,
By the NF control described later, the electric field strength at each transmission frequency registered in the preset number 1 is recorded in another storage area in the RAM 21.

When the record of the electric field strength in the NF control makes one round with respect to the registered transmission frequencies, the record is read and the registration order of the registered transmission frequencies is rearranged in descending order of the electric field strength. To be

However, if there is a transmission frequency in which the different PI flag is set to 1, the registration order of these transmissions is the last one, and there is no gap in the registration order.
Can be rearranged. The same is true even if another preset number is selected.

<< Explanation of NF Control >>
... Next, the NF control will be described. FIG. 5 shows N executed by the CPU 19.
It is a flow chart which shows an example of F control. The control is
It is repeatedly executed intermittently. Now, it is assumed that the listener operates the operation panel 23 to select the preset number 1.

If there are a plurality of transmission frequencies registered in the preset number 1, the transmission frequencies to be controlled are circulated according to the registration order every time the control is executed. In other words, it starts from registration number 1 and returns to number 1 when it reaches the end. The transmission frequency to be controlled is tentatively referred to as a target transmission frequency.

An area for recording the electric field strength at each transmission frequency registered in the preset number 1 is secured in the other storage area in the RAM 21. Also,
In another storage area in the RAM 21, it is assumed that the transmission frequency of the broadcasting station being received and its electric field strength are recorded.

In step H50, the different PI flag corresponding to the target transmission frequency is examined. If the different PI flag is set to 1, the control ends. On the other hand, if 0, the control shifts to step H51. In step H51, the PI-free flag corresponding to the target transmission frequency is examined.

If the PI-free flag is set to 1,
The control proceeds to step H55. In step H55, the mute control 45 output from the port 14 is set to instruct the mute on. Therefore, the drive of the speaker 13 by the reproduction circuit 12 is suppressed until the mute control 45 is set to instruct the mute off. Then, the control shifts to step H56.

In step H56, the reception frequency f _TUNE output from the port 18 is set to indicate the target transmission frequency. Therefore, the audio broadcast signal received at the target transmission frequency is received from the tuner circuit 11.
40, the digital broadcast signal 41, and the electric field strength 42 and IFD 43 near the target transmission frequency are output. Then, the control shifts to step H57.

On the other hand, in step H51, the non-P
If the I flag is set to 0, the control is in step H52.
Move to. In step H52, the mute on control is executed. Then, the control shifts to step H53. In step H53, the reception frequency changing control to the target transmission frequency is executed, and the control is step H
Move to 54.

In step H54, the mute control 45 output from the port 14 is set to instruct mute off. Therefore, the playback circuit 12 speaker
13 will be driven. Then, the control shifts to step H57.

In step H57, the IFD 43 is read in via the port 18 and inspected. If the IFD 43 indicates that a radio wave exists at the reception frequency, the control shifts to step H58.

In step H58, the data demodulation circuit
15 checks whether digital broadcasting can be demodulated. If the broadcast PI code can be read via the port 16, it can be demodulated. If the demodulated PI code can be read, the control shifts to step H59.

In step H59, the PI code stored in the preset No. 1 is compared with the PI code read in step H58. If the collations match, the control shifts to step H60, the different PI flag corresponding to the target transmission frequency is set to 0, and further the control shifts to step H61 to set the non-PI flag corresponding to the target transmission frequency. The flag is also set to 0. Then, the control shifts to step H62.

In step H62, the electric field strength converted into the digital value is read in through the port 18,
It is compared with the electric field strength of the broadcasting station which was being received immediately before the start of the control. If the former is larger, the control shifts to step H71, the mute off control is executed, and the control ends.

On the other hand, if the electric field strength of the broadcasting station which was being received immediately before the start of the control is higher, the control is step H70.
Then, the control of changing the reception frequency to the transmission frequency of the broadcasting station which is being received is executed, and the control is performed in the step H
Move to 71.

Further, the PI in the step H59
If the codes do not match, the control shifts to step H63, the different PI flag corresponding to the target transmission frequency is set to 1, and the control shifts to step H70.

The PI in step H58
If the code cannot be demodulated, the control shifts to step H64. In step H64, the electric field intensity reading is executed and compared with a predetermined value. The predetermined value is an experiment,
Alternatively, it is a value that is separately determined by calculation and is the minimum value of the electric field strength that can correctly demodulate the digital broadcast.

If the read electric field strength exceeds the predetermined value, the control shifts to step H65, the different PI flag corresponding to the target transmission frequency is set to 1, and the control shifts to step H70. On the other hand, if the read electric field strength does not reach the predetermined value, the control shifts to step H66, the PI-free flag corresponding to the target transmission frequency is set to 1, and the control shifts to step H70.

The IF in step H57
If D43 indicates that there is no radio wave at the reception frequency, the control shifts to step H67, and the electric field strength is compared with the predetermined value.

If the read electric field strength exceeds the predetermined value, the control shifts to step H69, the different PI flag corresponding to the target transmission frequency is set to 1, and the control shifts to step H70. On the other hand, if the read electric field strength does not reach the predetermined value, the control shifts to step H68, the PI-free flag corresponding to the target transmission frequency is set to 1, and the control shifts to step H70. Such control is similarly performed even if another preset number is selected.

<< Explanation of Action of NF Control According to the Present Invention >> Next, by taking a specific situation as an example, what action the NF control has will be described. explain. FIG. 6A is a graph showing the frequency characteristics of the transmission wave of each broadcasting station at a certain point.

In the figure, frequencies f _A1 , f _B , f
_A2 is the transmission frequency of the broadcasting stations A1, B, A2, respectively. Here, the broadcasting stations A1 and A2 are broadcasting stations of the same series, and the broadcasting station B is a broadcasting station of a different series. The listener is
It is assumed that the reception of the series broadcast to which the broadcasting stations A1 and A2 belong is designated.

In the electric field measurement of the broadcasting station A1, due to the spread of the sideband of the broadcasting station B, a measurement result indicating an electric field strength larger than that of the broadcasting station A2 is obtained. However, since the IFD 43 does not receive the adjacent channel interference, it indicates no radio wave.

According to the NF control of the radio receiver,
Under the circumstances, in the control execution for the broadcasting station A1, the steps H50, H51, H52, H53, H5 are executed.
Step H69 is executed through 4, H57 and H67. That is, the different PI flag corresponding to the transmission frequency of the broadcasting station A1 is set to 1. Then, steps H70 and H71 are executed, and the control ends.

In the NF control for the broadcasting station A1 executed after the control is executed, the broadcasting station A1
Since the different PI flag of 1 is set to 1, when step H50 is executed, the control ends. That is, the tuning control to the broadcasting station A1 is suppressed.

FIG. 7B is a time chart showing the audio reproduction state of the radio receiver under the above situation. Same figure
(b) As shown in (a), when the broadcasting station A2 is being received and reproduced, the tuning control to the broadcasting station A1 is temporarily performed, and the electric field strength of the broadcasting station A1 is the electric field strength of the broadcasting station A2. Since the electric field measurement result indicating that it is larger than
The PI code collation is performed.

During the PI code collating period, noise is reproduced as shown in FIGS. However, at that time, the different PI flag corresponding to the broadcasting station A1 is set to 1, and thereafter, the NF control for the broadcasting station A1 as shown in (b), (d), (e), and (f) of FIG. Is repeated, but tuning control to the broadcasting station A1 in which the different PI flag is set to 1 is not performed, and the audio reproduction of the broadcasting station A2 is interrupted as shown in (b) and (c) of FIG. There is no.

Incidentally, in the storage structure of the AF list, the transmission frequency for which the different PI flag is set to 1 is controlled by the control means for storing the transmission frequency of the affiliated station so that the registration frequency is the last. .

Therefore, for example, if the maximum registration order of each preset is set to about 20, while the transmission frequencies of affiliated stations that are broadcast one after another are newly registered, the transmission frequency with the different PI flag set to 1 is set. Will be discarded when the registered frequency is full.

When the transmission frequency having the different PI flag set to 1 is discarded and the frequency is broadcast again as the transmission frequency of the same series, the frequency is registered as a new frequency. As a result, the frequency becomes
It becomes the control target of F control.

[0082]

As described above, in the radio receiver of the present invention, although the actual electric field strength is weak, adjacent channel interference occurs and a measurement result indicating a larger electric field strength than the actual one is obtained. However, even if there is such a situation, the structure is such that the reproduction of the broadcast is not repeated twice or more. Therefore, unlike the conventional case, the broadcast being received is no longer intermittently interrupted by the adjacent channel interference.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic principle of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a graph showing reception characteristics of a tuner circuit suitable for the present invention.

FIG. 4 is a diagram showing a storage structure of an AF list suitable for the present invention.

FIG. 5 is a flowchart showing NF control suitable for the present invention.

FIG. 6 is a diagram illustrating the operation of the present invention.

FIG. 7 is a flowchart illustrating conventional NF control.

FIG. 8 is a diagram illustrating a problem in conventional NF control.

[Explanation of symbols]

1 tuning means 2 audio reproduction means 3 data demodulation means 4 control means 5 affiliated station storage means 10 antenna 11 tuner circuit 12 audio reproduction circuit 13 speaker 14 port 15 data demodulation circuit 16 port 17 A / D converter 18 port 19 CPU 20 ROM 21 RAM 22 Port 23 Operation panel 30 Bus 40 Audio broadcasting signal 41 Digital broadcasting signal 42 Electric field strength 43 IFD f _TUNE Reception frequency 45 Mute control

Claims (1)

[Claims] 1. Tuning means (1) for receiving a radio wave and outputting a detection signal and an electric field strength near the tuning frequency in synchronization with a frequency designated by the control means (4); and the tuning means (1). Audio reproduction means (2) for reproducing an audio broadcast from the output detection signal, data demodulation means (3) for demodulating a digital broadcast from the detection signal output by the tuning means (1), and the data demodulation means (3) The transmission frequency of the same-series station broadcast by the digital broadcasting demodulated by is intermittently designated to the tuning means (1), and the tuning means (1)
A radio receiver having a control means (4) for investigating an electric field strength output by the tuning means (1), wherein the tuning means (1) measures and outputs a narrow band electric field strength in the vicinity of a tuning frequency. The affiliated station storage means (5) having a storage area for storing the transmission frequencies of the above and a storage area for marking the transmission frequencies in an identifiable manner, and the control means (4) includes the data demodulation means (3) Means for storing in the affiliated station storage means (5) the transmission frequency of the same affiliated station demodulated by, and the electric field strength output by the tuning means (1) among these transmission frequencies is a predetermined value or more, and, A means for distinguishably marking the narrow band electric field strength output by the tuning means (1) that does not reach a predetermined value and storing it in the affiliated station storage means (5), and the transmission frequency marked in this way as the tuning Designated as means (1) A radio receiver having means for suppressing noise.