JP7492347B2 - Receiving device and receiving method - Google Patents

Description

The present invention relates to a receiving device and a receiving method.

The technology of Patent Document 1 is known as a technology related to phase diversity reception. The abstract of Patent Document 1 states, "The radio receiving device has a main tuner and a sub tuner connected to a main antenna and a sub antenna, respectively, a determination means for determining the reception state from the electric field strength of the received signals from the main tuner and the sub tuner, and a reception control means for enabling the main tuner and the sub tuner to operate independently when the determination means determines that the reception state is good, and for causing the main tuner and the sub tuner to perform phase diversity reception when the reception state is determined to be poor."

JP 2007-60624 A

However, the technique of Patent Document 1 leaves room for improvement in terms of determining the reception operations of the main tuner and the sub tuner.
An object of the present invention is to provide a receiving device and a receiving method that can more appropriately determine the receiving operations of two tuners.

The present invention relates to a signal processing device including a first receiving unit and a second receiving unit respectively connected to at least two antennas, an acquisition unit that acquires a first field strength of a signal received by the first receiving unit and a second field strength of a signal received by the second receiving unit, a calculation unit that calculates a field strength difference which is a value obtained by subtracting the first field strength from the second field strength, a storage unit that stores a preset field strength threshold, a preset first field strength difference threshold, and a preset second field strength difference threshold which is set to a field strength difference greater than the first field strength difference threshold, and a storage unit that, when the first field strength is greater than the field strength threshold, compares the field strength difference with the second field strength difference threshold, and , when the field strength difference is greater than the second field strength difference threshold, compares the field strength difference with the second field strength difference threshold, and, when the field strength difference is greater than the second field strength difference threshold, calculates a field strength difference between the first receiving unit and the second receiving unit. a control unit that causes a second receiving unit to perform a phase diversity receiving operation in which the first receiving unit and the second receiving unit receive the same frequency, and, if the field strength difference is equal to or less than the second field strength difference threshold, causes the second receiving unit to perform a seek operation in which the second receiving unit receives a frequency of a broadcast station different from the broadcast station being received by the first receiving unit while the first receiving unit is receiving a broadcast, and, if the first field strength is equal to or less than the field strength threshold, compares the field strength difference with the first field strength difference threshold, and, if the field strength difference is greater than the first field strength difference threshold, causes the first receiving unit and the second receiving unit to perform the phase diversity receiving operation, and, if the field strength difference is equal to or less than the first field strength difference threshold, causes the seek operation.

The present invention makes it possible to more appropriately determine the reception operation of two tuners.

1 is a block diagram showing a schematic configuration of an in-vehicle receiving device according to an embodiment of the present invention; 4 is a flowchart showing the operation of the in-vehicle receiving device. FIG. 2 is an explanatory diagram of the operation of the in-vehicle receiving device. 13 is a flowchart of a reception operation determination process. FIG. 4 is a diagram showing input/output characteristics of a main tuner and a sub tuner.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, an in-vehicle receiving device will be described as one aspect of the receiving device of the present invention.
FIG. 1 is a block diagram showing a schematic configuration of an in-vehicle receiving device 1 according to this embodiment.
The in-vehicle receiving device 1 is mounted on a vehicle, which is an example of a moving body, and is a receiving device that receives multiplex broadcasting in the RDS (Radio Data System) system. The RDS system is a system in which the transmitting side transmits a broadcast wave W in which data Hb indicating appropriate information is multiplexed with a broadcast signal Ha, and the receiving side extracts the multiplexed data Hb from the broadcast wave W. Furthermore, the in-vehicle receiving device 1 of this embodiment has a phase diversity receiving function that receives the broadcast wave W of the same frequency using multiple tuners.

As shown in FIG. 1, the in-vehicle receiving device 1 includes a main antenna 10M, a sub-antenna 10S, a main tuner 12M, a sub-tuner 12S, a DSP (Digital Signal Processor) 14, and a control computer 20. An amplifier 16 and a speaker 18 provided in the vehicle are connected to the output stage of the DSP 14.

The main antenna 10M and the sub-antenna 10S are circuit components that receive broadcast radio waves from multiple broadcast stations and output the received signal, and are installed in the vehicle in a manner suitable for phase diversity reception operation. The main antenna 10M is connected to the main tuner 12M and outputs the received signal to the main tuner 12M. The sub-antenna 10S is connected to the sub-tuner 12S and outputs the received signal to the sub-tuner 12S.

The main tuner 12M and the sub-tuner 12S are receiving units (first receiving unit and second receiving unit) that receive the broadcast signal Ha of the broadcast wave W of the broadcast station (hereinafter referred to as the "selected station") selected by the control computer 20 based on the reception signal of the main antenna 10M and the sub-antenna 10S. In addition, both the main tuner 12M and the sub-tuner 12S have the function of performing the phase diversity reception operation described above. Furthermore, in this embodiment, the sub-tuner 12S has an RDS reception function that, in addition to receiving the broadcast signal Ha, receives data Hb multiplexed onto the broadcast signal Ha.

As shown in FIG. 1, each of the main tuner 12M and the sub-tuner 12S includes a front end 30, a detection circuit 32, and a field intensity detection circuit .
The front end 30 is a circuit that converts a reception signal of the reception frequency of the selected station into an intermediate frequency signal and amplifies it. The detection circuit 32 is a circuit that detects the intermediate frequency signal amplified by the front end 30 based on the frequency of the selected station and outputs a broadcast signal Ha. The field strength detection circuit 36 detects the field strength of the broadcast wave W of the selected station based on the broadcast signal Ha output from the detection circuit 32 and outputs the field strength to the control computer 20. The field strength detection circuit 36 is also called an "S meter." In the following, the field strength output by the main tuner 12M is given the symbol IM, and the field strength output by the sub-tuner 12S is given the symbol IS to distinguish between the respective field strengths.

The DSP 14 has an audio demodulation circuit that demodulates the broadcast audio signal based on the broadcast signal Ha output from the main tuner 12M and the sub tuner 12S. The audio signal is output from the DSP 14 to the amplifier 16, amplified by the amplifier 16, and then output to the speaker 18, from which it is emitted into the vehicle cabin.

In addition, when the main tuner 12M and the sub tuner 12S perform phase diversity reception, the DSP 14 performs appropriate phase diversity signal processing that is publicly known or well-known, to combine or selectively switch the audio signals obtained from the broadcast signals Ha of the main tuner 12M and the sub tuner 12S. This makes it possible to obtain audio signals with reduced noise even when the reception conditions of the main antenna 10M are poor.

In this embodiment, in addition to the above-mentioned circuits, the subtuner 12S includes, as a configuration for RDS reception operation, a filter circuit 38 that extracts a data signal Hbs containing only the data Hb component from the broadcast signal Ha of the detection circuit 32 and outputs it to the DSP 14, and a selector circuit 39 that switches the output destination of the detection circuit 32 to the filter circuit 38. The DSP 14 has a built-in data demodulation circuit that demodulates the data Hb from the data signal Hbs, and outputs the data Hb demodulated by the data demodulation circuit to the control computer 20.

The control computer 20 is a device that controls the receiving operations of the main tuner 12M and the sub-tuner 12S and the operation of the DSP 14, and in this embodiment, a so-called microcomputer is used.
The control computer 20 includes a processor such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), a memory device (also called a main memory device) such as a ROM (Read Only Memory) or RAM (Random Access Memory), an interface circuit for connecting circuits such as the main tuner 12M, the sub tuner 12S, and the DSP 14, and a timer circuit that measures elapsed time based on a clock signal input from outside or generated by the control computer 20 itself, and the processor executes computer programs stored in the memory device to realize various functional configurations.

As shown in FIG. 1, the control computer 20 of this embodiment has a functional configuration including a field intensity acquisition unit 51, a phase diversity control unit 52, and a seek operation control unit 53.

The electric field strength acquisition unit 51 acquires electric field strengths IM and IS from the main tuner 12M and the sub tuner 12S, respectively.
The phase diversity control section 52 causes both the main tuner 12M and the sub-tuner 12S to receive the broadcast radio waves W of the same frequency and perform phase diversity reception.
The seek operation control unit 53 controls the seek operation of the broadcast station. The seek operation is a receiving operation in which the main tuner 12M and the sub tuner 12S sequentially change the frequency to be received and sequentially output the broadcast signal Ha for the changed frequency. Such seek operation control is used, for example, to detect a frequency at which a broadcast station is present in a predetermined frequency band.

The seek operation control is also used when the subtuner 12S operating as an RDS receiver acquires data Hb from each of a plurality of broadcast stations (hereinafter referred to as "each broadcast station data acquisition operation"). In this each broadcast station data acquisition operation, the seek operation control unit 53 changes the frequency received by the subtuner 12S in succession to cause the subtuner 12S to receive the broadcast signal Ha of each broadcast station in sequence, and acquires data Hb obtained from each broadcast signal Ha from the DSP 14.
The operation of acquiring data from each broadcasting station is used to create a program list that lists information about programs broadcast by each broadcasting station.
The frequency of each broadcasting station is stored in advance in, for example, a memory device, etc. In this case, the frequency of the broadcasting station may be a frequency detected by the seek operation control described above, or may be a frequency preset at the time of shipment from the factory, etc.

The control computer 20 of this embodiment also includes a control unit 56 that controls the receiving operation of the main tuner 12M and the sub tuner 12S using the phase diversity control unit 52 and the seek operation control unit 53. In this embodiment, the receiving operation is a phase diversity receiving operation controlled by the phase diversity control unit 52 and a seek operation by the seek control unit 54.

In the in-vehicle receiving device 1 of this embodiment, the receiving operations performed by the main tuner 12M and the sub-tuner 12S are controlled by the control unit 56 according to the electric field strength IM of the main tuner 12M. For such control, the control computer 20 further includes a threshold memory unit 60, an electric field strength difference calculation unit 62, and a determination unit 64.

The threshold storage unit 60 pre-stores a field strength difference threshold K. The field strength difference threshold K is a threshold for determining the reception operations to be performed by the main tuner 12M and the sub tuner 12S based on the field strength difference DE. The field strength difference DE is a value obtained by subtracting the field strength IM of the main tuner 12M from the field strength IS of the sub tuner 12S (i.e., "field strength IS - field strength IM").
Furthermore, a plurality of (two in this embodiment) field strength difference thresholds K and a field strength threshold L for the field strength IM of the main tuner 12M are pre-stored in the threshold storage unit 60. The plurality of field strength difference thresholds K and the field strength threshold L will be described later.

The field intensity difference calculation unit 62 is a calculation unit that calculates the field intensity difference DE based on the field intensities IM and IS of the main tuner 12M and the sub tuner 12S, respectively.
The determination unit 64 determines one field strength difference threshold K from among a plurality of field strength difference thresholds K based on the field strength IM of the main tuner 12M and the field strength threshold L, and determines the reception operation to be performed by the main tuner 12M and the sub-tuner 12S based on the field strength difference threshold K and the field strength difference DE. Through this determination, either a phase diversity reception operation or a seek operation is determined as the reception operation to be performed by the main tuner 12M and the sub-tuner 12S.
The control unit 56 controls the receiving operations of the main tuner 12M and the sub-tuner 12S based on the determination result of the determination unit 64, and causes them to perform a phase diversity receiving operation or a seek operation.

Next, the operation of the vehicle-mounted receiving device 1 of this embodiment will be described.
In this operation explanation, the vehicle-mounted receiving device 1 will be described as operating when, while receiving the broadcast signal Ha of the selected station through the main tuner 12M and outputting an audio signal, the sub-tuner 12S executes the above-mentioned operation of acquiring data from each broadcast station as a seek operation, for example to create a program list.

FIG. 2 is a flowchart showing the operation of the in-vehicle receiving device 1.
In order to sequentially receive the broadcast signals Ha of each broadcast station, first, the control unit 56 reads out a list of frequencies of each broadcast station (hereinafter referred to as a "frequency list") from a memory device or the like (step Sa1).

Next, prior to the seek operation control by the seek operation control unit 53, the determination unit 64 executes a reception operation determination process (step Sa2). The reception operation determination process is a process for determining whether the reception operation to be performed by the main tuner 12M and the sub tuner 12S is a phase diversity reception operation or a broadcast station data acquisition operation (seek operation).
In this reception operation determination process, if a relatively large improvement in the S/N ratio of the audio signal is expected by performing phase diversity reception operation of the main tuner 12M and the sub tuner 12S, a phase diversity reception operation is determined as the reception operation. On the other hand, if the improvement in the S/N ratio is small, a broadcast station data acquisition operation is determined as the reception operation. The details of this reception operation determination process will be described later.

If, as a result of the reception operation determination process by the determination unit 64, it is determined that the reception operation is a broadcast station data acquisition operation (step Sa3:A), the control unit 56 controls the seek operation control unit 53 to cause the sub-tuner 12S to perform a seek operation to receive the broadcast signal Ha of one of the broadcast stations while causing the main tuner 12M to continue receiving the selected station (step Sa4).
Specifically, the seek operation control unit 53 instructs the sub-tuner 12S on the frequency of the broadcast station to be received based on the frequency list, and causes the sub-tuner 12S to receive the broadcast signal Ha of that frequency.

The control unit 56 then uses a timer circuit to monitor the passage of a predetermined time A, and if this predetermined time A has passed (step Sa5: Yes), and there is a broadcast station that has not been received (step Sa6: Yes), the processing procedure returns to step Sa2 to have the sub-tuner 12S receive the broadcast signal Ha of that broadcast station. Then, in this step Sa2, the determination unit 64 again performs a reception operation determination.

The predetermined time A in step Sa5 is set based on the time required from when the subtuner 12S starts receiving the broadcast signal Ha until the DSP 14 outputs the data Hb multiplexed onto the broadcast signal Ha, and is generally several tens of ms. When the data Hb is output from the DSP 14, the control computer 20 executes appropriate processing, such as storing the data Hb, at an appropriate timing.

If the reception operation determination process in step Sa3 determines that the reception operation is a phase diversity reception operation (step Sa3: B), the control unit 56 controls the phase diversity control unit 52 to cause the main tuner 12M and the sub-tuner 12S to perform phase diversity reception operation (step Sa7). This process switches the sub-tuner 12S, which had been performing a data acquisition operation (seek operation) for each broadcast station, to a phase diversity reception operation, and the broadcast station data acquisition operation is interrupted.

The control unit 56 then monitors the passage of the predetermined time A, and if the predetermined time A has passed (step Sa5: Yes), since the broadcast signal Ha for the broadcast station before the broadcast station data acquisition operation was interrupted has not been received (step Sa6: Yes), the control unit 56 returns the processing procedure to step Sa2 in order to receive the broadcast signal Ha for that broadcast station.

FIG. 3 is a diagram illustrating the operation of the in-vehicle receiving device 1, and is a schematic diagram showing the audio signal output from the in-vehicle receiving device 1 during broadcast station data acquisition operation, together with the audio signal output by the main tuner 12M.
When the in-vehicle receiving device 1 receives the broadcast signal Ha of the selected station by the main tuner 12M, audio signals based on the broadcast signal Ha are sequentially output as shown in the figure.
It is also assumed that the reception environment changes as the vehicle travels, and that during a certain period Ca, the audio signal output from the main tuner 12M contains relatively large amounts of noise, and that the S/N ratio of the audio signal is expected to be improved by phase diversity reception operation.
In this case, the judgment unit 64 judges that the receiving operation is phase diversity receiving operation through the receiving operation judgment process of step Sa3 above, so that phase diversity receiving operation is performed during this period Ca, and an audio signal with suppressed noise is output from the in-vehicle receiving device 1.
On the other hand, outside the period Ca, the determination unit 64 determines that the reception operation is a broadcast station data acquisition operation (seek operation) through the reception operation determination process of step Sa3, whereby the broadcast station data Hb is acquired sequentially.

Incidentally, during the operation of acquiring data from each broadcast station (during the seek operation), the reception time of the subtuner 12S for each broadcast station is approximately the above-mentioned predetermined time A, which is set to a relatively short time of several tens of ms. Therefore, if the number of broadcast stations that the subtuner 12S receives during the seek operation is, for example, only one station, and the main tuner 12M and the subtuner 12S immediately perform phase diversity reception operation after this seek operation, the time for which noise is output by the seek operation is approximately several tens of ms.
In this case, since the noise lasts for a very short period of time, it is difficult for passengers to notice the noise and the noise is rarely unpleasant to the ears.

However, during the operation of acquiring data from each broadcast station, the sub-tuner 12S performs reception operations for multiple broadcast stations, so noise is output continuously for a period of time corresponding to the number of broadcast stations to be received, and unless some countermeasure is taken, the noise becomes unpleasant to the ear.
In contrast, according to this embodiment, even during the operation of acquiring data from each broadcasting station, the judgment unit 64 judges the reception operation each time before the sub-tuner 12S receives the broadcast signal Ha from the broadcasting station, and if the phase diversity reception operation is expected to improve the S/N ratio of the audio signal, the reception operation is judged to be the phase diversity reception operation.
As a result, even during the operation of acquiring data from each broadcast station, noise is not output for longer than the predetermined time A, and the output of harsh noise is reliably suppressed.

Next, the above-mentioned reception operation determination process will be described in detail.
FIG. 4 is a flowchart of the reception operation determination process.
In the control computer 20, the electric field strength acquisition unit 51 first acquires the electric field strengths IM and IS from the main tuner 12M and the sub-tuner 12S, respectively (step Sb1). Next, the electric field strength difference calculation unit 62 calculates the above-mentioned electric field strength difference DE based on these electric field strengths IM and IS (step Sb2).

Next, the determination unit 64 determines one of the multiple field strength difference thresholds K stored in the threshold storage unit 60 based on the field strength IM of the main tuner 12M (step Sb3). The determination unit 64 then compares the field strength difference DE with the field strength difference threshold K, and if the field strength difference DE is equal to or less than the field strength difference threshold K (step Sb4: Yes), the determination unit 64 determines that the main tuner 12M and the sub-tuner 12S should perform a data acquisition operation (seek operation) for each broadcast station as the reception operation to be performed by the sub-tuner 12S (step Sb5). On the other hand, if the field strength difference DE exceeds the field strength difference threshold K (step Sb4: No), the determination unit 64 determines that the main tuner 12M and the sub-tuner 12S should perform a phase diversity reception operation as the reception operation to be performed by the main tuner 12M and the sub-tuner 12S (step Sb6).

The field strength difference threshold K is a value indicating the field strength difference DE at which a relatively large improvement in the S/N ratio of an audio signal is expected by operating the main tuner 12M and the sub tuner 12S in phase diversity reception mode.
The electric field strength difference threshold K will be described in detail below.

FIG. 5 is a diagram showing the input/output characteristics of the main tuner 12M and the sub-tuner 12S.
As shown in the figure, in the input/output characteristics of the main tuner 12M and the sub tuner 12S, as the electric field strength increases, the output level of the broadcast signal Ha (in the figure, labeled "Signal") increases, while the output level of the noise (in the figure, labeled "Noise") tends to decrease.
In the medium to strong electric field strength range Ra where the electric field strength becomes relatively large (in the illustrated example, the range where the electric field strength is approximately 20 (dBuV) or more), the output level of the broadcast signal Ha becomes approximately constant, and the change in the S/N ratio in response to an increase or decrease in the electric field strength also tends to be gradual.
On the other hand, in the weak electric field strength range Rb, where the electric field strength is lower than that in the medium-to-strong electric field strength range Ra, the output levels of the broadcast signal Ha and noise are not stable in response to increases and decreases in electric field strength, and there is a tendency for the S/N ratio to change significantly in response to increases and decreases in electric field strength.

For example, in the figure, points (I) and (II) belonging to the weak electric field strength range Rb, and points (III) and (IV) belonging to the medium-strong electric field strength range Ra, all have the same electric field strength difference DE of 5 (dBuV). However, the difference in S/N ratio between points (I) and (II) is larger than the difference in S/N ratio between points (III) and (IV), and even with the same electric field strength difference DE, there is a large difference in S/N ratio between the medium-strong electric field strength range Ra and the weak electric field strength range Rb.
In other words, in the medium to strong electric field strength range Ra, the electric field strength difference DE that causes the same degree of fluctuation in the S/N ratio as in the weak electric field strength range Rb is larger than that in the weak electric field strength range Rb.
Therefore, even if the field strength difference DE in the weak field strength range Rb significantly improves the S/N ratio of the audio signal through phase diversity reception operation, in the medium to strong field strength range Ra, the S/N ratio will not improve significantly even if phase diversity reception operation is performed.

Therefore, in this embodiment, the field strength difference threshold K for the medium-to-strong field strength range Ra (hereinafter referred to as the "second field strength difference threshold K2") is set to a larger value than the field strength difference threshold K for the field strength difference DE for phase diversity reception operation in the weak field strength range Rb (hereinafter referred to as the "first field strength difference threshold K1").
As a result, in the medium-strong electric field strength range Ra, a larger electric field strength difference DE occurs between the main tuner 12M and the sub-tuner 12S, and the phase diversity reception operation is suppressed until the phase diversity reception operation is expected to improve the S/N ratio, thereby extending the period during which the sub-tuner 12S can perform seek operations without being restricted by the phase diversity reception operation.

The threshold memory unit 60 pre-stores two electric field strength difference thresholds K: the first electric field strength difference threshold K1 and a second electric field strength difference threshold K2, which is set to an electric field strength difference DE greater than the first electric field strength difference threshold K1.
The threshold storage unit 60 also stores a field strength threshold L for determining whether the field strength IM of the main tuner 12M belongs to the medium-strong field strength range Ra or the weak field strength range Rb.
When the input/output characteristics of the main tuner 12M and the sub tuner 12S are the example shown in Figure 5, for example, the first field strength difference threshold K1 is set to 5 (dBuV), the second field strength difference threshold K2 is set to 7 (dBuV), and the field strength threshold L is set to 20 (dBuV).

Then, in step Sb3 of the above-mentioned reception operation determination process, the determination unit 64 compares the field strength IM of the main tuner 12M with the field strength threshold L, and determines whether the field strength IM belongs to the medium-strong field strength range Ra or the weak field strength range Rb based on whether the field strength IM exceeds the field strength threshold L. If the field strength IM belongs to the medium-strong field strength range Ra, the determination unit 64 selects the second field strength difference threshold K2 as the field strength difference threshold K. If the field strength IM belongs to the weak field strength range Rb, the determination unit 64 selects the first field strength difference threshold K1 as the field strength difference threshold K.

The electric field strength difference threshold value K selected in this manner is used for comparison with the electric field strength difference DE in the judgment of step Sb4. In the medium to strong electric field strength range Ra, even if the electric field strength difference DE is somewhat large, if a significant improvement in the S/N ratio of the audio signal is not expected, the receiving operation is judged to be an operation to acquire data from each broadcasting station, rather than a phase diversity receiving operation.
This makes it possible to reduce the number of phase diversity reception operations, which are not very effective in improving the S/N ratio of audio signals. Also, by reducing the number of phase diversity reception operations during each broadcast station data acquisition operation, the broadcast station data acquisition operation can be completed more quickly.

This embodiment provides the following advantages:

In the in-vehicle receiving device 1 of this embodiment, the control unit 56 controls the receiving operation of the main tuner 12M and the sub-tuner 12S based on a comparison of the electric field strength IM (first electric field strength) of the main tuner 12M with the electric field strength threshold L, and a comparison of the electric field strength difference DE with the first electric field strength difference threshold K1 or the second electric field strength difference threshold K2.
This makes it possible to more appropriately control the reception operations of the main tuner 12M and the sub tuner 12S.

In the in-vehicle receiving device 1 of this embodiment, the control unit 56 controls, as a receiving operation, a phase diversity receiving operation in which the main tuner 12M and the sub-tuner 12S receive the same frequency.
Therefore, the control unit 56 can cause the main tuner 12M and the sub-tuner 12S to perform phase diversity reception operation at an appropriate timing when an improvement in the S/N ratio of the audio signal (output signal) is expected.

In the in-vehicle receiving device 1 of this embodiment, the control unit 56 controls, as a receiving operation, a seek operation in which, while the main tuner 12M is receiving a broadcast of a selected station, the sub-tuner 12S receives a frequency of a broadcast station different from the frequency of the selected station.
Therefore, at a timing when a significant improvement in the S/N ratio of the audio signal (output signal) is not expected, the control unit 56 can cause the sub-tuner 12S, out of the main tuner 12M and the sub-tuner 12S, to perform a seek operation.

In the in-vehicle receiving device 1 of this embodiment, in the seek operation, the sub-tuner 12S receives the frequencies of a plurality of broadcasting stations at predetermined intervals A.
This makes it possible to efficiently create, for example, the program list for each broadcasting station described above while maintaining a good S/N ratio and avoiding the generation of noise.

In the in-vehicle receiving device 1 of this embodiment, the first field strength difference threshold K1 is used when the field strength IM of the main tuner 12M is equal to or less than the field strength threshold L. On the other hand, the second field strength difference threshold K2 is used when the field strength IM of the main tuner 12M exceeds the field strength threshold L, and a field strength difference DE larger than the first field strength difference threshold K1 is set.
As a result, an appropriate electric field strength difference DE according to the electric field strength IM of the main tuner 12M is set for each of the first electric field strength difference threshold K1 and the second electric field strength difference threshold K2, and the reception operation can be determined more accurately using these first electric field strength difference threshold K1 and second electric field strength difference threshold K2.

The above-described embodiment is merely an example of one aspect of the present invention, and any modification or application is possible without departing from the spirit of the present invention.

In the above-described embodiment, the vehicle-mounted receiving device 1 may have three or more antennas, each of which may be connected to a tuner that is a receiving unit.

In the above-described embodiment, the main tuner 12M may have a function of receiving data Hb multiplexed onto the broadcast signal Ha, similar to the sub-tuner 12S. In other words, the main tuner 12M and the sub-tuner 12S may have the same configuration.

The receiving device according to the present invention can be mounted on any suitable moving object, such as a mobile electronic device, not limited to a vehicle.

The functional blocks shown in FIG. 1 are schematic diagrams in which components are classified according to the main processing content in order to facilitate understanding of the present invention, and each component can be further classified into more components according to the processing content. Also, a single component can be classified to perform even more processing.

1. Vehicle-mounted receiving device (receiving device)
10M Main Antenna (Antenna)
10S Sub-antenna (antenna)
12M Main Tuner (First Receiving Unit)
12S Sub-tuner (second receiver)
20 Control computer (computer)
36 Field strength detection circuit 51 Field strength acquisition unit 52 Phase diversity control unit 53 Seek operation control unit 54 Seek control unit 56 Control unit 60 Threshold memory unit (memory unit)
62 Electric field strength difference calculation unit (calculation unit)
Ca Period DE Field strength difference Ha Broadcast signal Hb Data Hbs Data signal IM Field strength (first field strength)
IS Electric field strength (second electric field strength)
K: Field strength difference threshold K1: First field strength difference threshold K2: Second field strength difference threshold L: Field strength threshold Ra: Medium-strong field strength range Rb: Weak field strength range W: Broadcast radio wave

Claims (2)

a first receiving unit and a second receiving unit respectively connected to at least two antennas;
an acquisition unit that acquires a first electric field intensity of a signal received by the first receiving unit and a second electric field intensity of a signal received by the second receiving unit;
a calculation unit that calculates an electric field intensity difference that is a value obtained by subtracting the first electric field intensity from the second electric field intensity;
a storage unit that stores a preset electric field strength threshold, a preset first electric field strength difference threshold , and a preset second electric field strength difference threshold that is set to a field strength difference greater than the first electric field strength difference threshold;
If the first electric field strength is greater than the electric field strength threshold, comparing the electric field strength difference with the second electric field strength difference threshold;
When the electric field strength difference is greater than the second electric field strength difference threshold, causing the first receiving unit and the second receiving unit to execute a phase diversity receiving operation in which the first receiving unit and the second receiving unit receive the same frequency;
when the electric field strength difference is equal to or less than the second electric field strength difference threshold, while the first receiving unit is receiving a broadcast, executing a seek operation in which the second receiving unit receives a frequency of a broadcast station different from a broadcast station currently being received by the first receiving unit;
If the first electric field strength is equal to or less than the electric field strength threshold, comparing the electric field strength difference with the first electric field strength difference threshold;
When the electric field strength difference is greater than the first electric field strength difference threshold, causing the first receiving unit and the second receiving unit to execute the phase diversity receiving operation;
a control unit that executes the seek operation when the electric field strength difference is equal to or smaller than the first electric field strength difference threshold;
A receiving device comprising: A receiving method for a receiving device including a first receiving unit and a second receiving unit respectively connected to at least two antennas, comprising:
A first step of acquiring a first electric field strength of a signal received by the first receiving unit and a second electric field strength of a signal received by the second receiving unit;
a second step of calculating a field strength difference, which is a value obtained by subtracting the first field strength from the second field strength;
a third step of controlling reception operations of the first receiving unit and the second receiving unit based on a comparison between the first electric field strength and a preset electric field strength threshold, and a comparison between the electric field strength difference and a preset first electric field strength difference threshold or a preset second electric field strength difference threshold that is set to a field strength difference greater than the first electric field strength difference threshold ;
Equipped with
The third step is
If the first electric field strength is greater than the electric field strength threshold, comparing the electric field strength difference with the second electric field strength difference threshold;
When the electric field strength difference is greater than the second electric field strength difference threshold, causing the first receiving unit and the second receiving unit to execute a phase diversity receiving operation in which the first receiving unit and the second receiving unit receive the same frequency;
when the electric field strength difference is equal to or less than the second electric field strength difference threshold, while the first receiving unit is receiving a broadcast, executing a seek operation in which the second receiving unit receives a frequency of a broadcast station different from a broadcast station currently being received by the first receiving unit;
If the first electric field strength is equal to or less than the electric field strength threshold, comparing the electric field strength difference with the first electric field strength difference threshold;
When the electric field strength difference is greater than the first electric field strength difference threshold, causing the first receiving unit and the second receiving unit to execute the phase diversity receiving operation;
performing the seek operation when the field strength difference is equal to or less than the first field strength difference threshold .

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