JP4451716B2 - Mobile phone having broadcast receiving function and control method thereof - Google Patents

Description

  The present invention relates to a mobile phone having a broadcast receiving function, and more particularly to a broadcast audio mute function.

  In recent years, in order to meet various needs of users, mobile phones (hereinafter referred to as multi-function mobile phones) to which various functions such as a broadcast receiving function and a photographing function are added in addition to the original call function have been put into practical use. Of course, the user expects a good feeling of use for such additional functions. As for the broadcast receiving function, for example, a mute function is used to give a good feeling to the user.

The mute function is a function that improves the audibility by suppressing inter-station noise by stopping the output of broadcast audio when the received signal level does not reach a predetermined threshold. It is a well-known technique that is commonly used. An example of a circuit for controlling such a mute function is disclosed in Patent Document 1, for example.
Japanese Patent Laid-Open No. 10-242877

However, when the conventional mute technique is applied to a multi-function mobile phone having a broadcast reception function as an additional function, the desired effect may not be obtained.
In a multi-function mobile phone, various clocks related to individual additional functions are used internally in addition to the local oscillation signal for wireless communication. For example, when the shooting function is used, a camera clock for driving the camera unit is used. Such a local oscillation signal or a clock signal can be a cause of impairing the mute function.

For example, when listening to a broadcast while using a photographing function, the received signal level may exceed a threshold value by weighting the received signal with a camera clock or its harmonics. When this happens, muting is canceled and the camera clock is emitted as noise, which greatly impairs the audibility.
In view of the above problems, an object of the present invention is to provide a mute technique suitable for a broadcast reception function of a multi-function mobile phone, and a mobile phone with a broadcast reception function using the technique.

In order to solve the above problem, the mobile phone of the present invention is a mobile phone having a broadcast receiving function for receiving a broadcast and muting a broadcast sound according to a received signal level, and is included in a frequency band used for the broadcast A noise source that generates noise intermittently, a first threshold value is set during the noise stop period, and a second threshold value that is greater than the first threshold value during the noise generation period Setting means for setting a value, and mute means for muting the broadcast sound based on a comparison between the received signal level and the set threshold value.
The noise source includes a local oscillator for wireless communication and a clock for driving at least one of a camera unit, a liquid crystal display, a memory card, a USB (Universal Serial Bus), and a voice recorder provided in the mobile phone. It may be a generator.

According to this configuration, since the mute threshold is changed between the noise stop period and the speech period, the broadcast can be normally heard during the noise stop period, and the noise is muted during the occurrence period. Thus, it is possible to provide the user with a good feeling of use at all times.
The setting means sets a first threshold value and a second threshold value for each of a plurality of frequencies included in a frequency band used for the broadcast, and the mute means Broadcast audio may be muted based on a comparison between a received signal level at a frequency and a threshold set for the selected channel frequency.

The setting means may set, for each frequency, a value obtained by adding the noise level at that frequency to the first threshold value as the second threshold value.
According to this configuration, it is possible to provide the user with a good feeling of use by controlling the mute using the optimum threshold value for each tuning frequency according to the frequency characteristics of the noise.
The mobile phone further compares the received signal level at the current channel selection frequency with a threshold set for the channel selection frequency, and sequentially selects the current channel selection frequency until a predetermined comparison result is obtained. You may provide the station search means to change.

According to this configuration, the usability of the station search function can be improved by the same operation as described above.
In order to solve the above problem, a control method of the present invention is a control method for a mobile phone having a broadcast receiving function for receiving a broadcast and muting a broadcast sound according to a received signal level, and the mobile phone is used for the broadcast A noise source that intermittently generates noise included in a certain frequency band, a first threshold value is set during the noise stop period, and from the first threshold value during the noise generation period A setting step for setting a second threshold value that is greater than the threshold value, and a mute step for muting the broadcast sound based on a comparison between the received signal level and the set threshold value.

The setting step sets a first threshold value and a second threshold value for each of a plurality of frequencies included in a frequency band used for the broadcast, and the mute step includes a current channel selection. Broadcast audio may be muted based on a comparison between a received signal level at a frequency and a threshold set for the selected channel frequency.
In the setting step, for each frequency, a value obtained by adding the noise level at the frequency to the first threshold value may be set as the second threshold value.

The control method further compares the received signal level at the current channel selection frequency with a threshold set for the channel selection frequency, and sequentially selects the current channel selection frequency until a predetermined comparison result is obtained. A station search step to change may be included.
By controlling the mobile phone according to these methods, the same effects as described above can be obtained.

  In order to solve the above problem, a program of the present invention is a computer-executable program for controlling a mobile phone having a broadcast receiving function for receiving a broadcast and muting a broadcast sound according to a received signal level. The mobile phone includes a noise source that intermittently generates noise included in a frequency band used for the broadcast, and causes a computer to execute the steps according to at least one of claims 6 to 9.

  By controlling the cellular phone using this program, the same effects as described above can be obtained.

The mobile phone according to the embodiment of the present invention is a multi-function mobile phone having at least a broadcast receiving function and a photographing function.
This mobile phone internally generates a camera clock for operating the camera unit only during a period in the shooting mode. The harmonics of the camera clock are included in the broadcast frequency band. The mobile phone sets different values for the threshold value for mute applied to the harmonic frequency in the camera clock stop period and the operation period, respectively.

  For example, the first threshold value during the camera clock stop period is set to the lowest received signal level that allows practical listening, and the second threshold value during the operation period is set to the first threshold value. Set the value to which the harmonic level is added. Accordingly, it is possible to normally listen to the broadcast during the stop period of the camera clock, and to mute the noise due to the harmonics during the operation period, thereby providing the user with a good feeling of use.

Hereinafter, the mobile phone will be described in detail with reference to the drawings.
<Overall configuration>
FIG. 1 is a functional block diagram showing the overall configuration of the mobile phone 1.
The cellular phone 1 includes an antenna 10, duplexers 11 and 12, a wireless receiver 20, a wireless transmitter 30, a power amplifier 31, a baseband processor 40, a broadcast receiver 50, an image sensor 60, a camera front end 61, and a receiver 81. , A microphone 82, a speaker 83, a display unit 84, an operation unit 85, and a memory card 86.

The baseband processing unit 40 includes an A / D converter 41 to 43, a D / A converter 44, a communication processing unit 45, an audio processing unit 46, a broadcast reception processing unit 56, a mute threshold table 57, a mute register 58, a channel selection A frequency register 59, an image processing unit 62, and a control unit 70 are included.
The baseband processing unit 40 includes, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a working memory, and a nonvolatile memory in addition to the A / D converters 41 to 43 and the D / A converter 44. It may be an IC (Integrated Circuit) chip to be configured. In that case, the communication processing unit 45, the audio processing unit 46, the broadcast reception processing unit 56, the image processing unit 62, and the control unit 70 are held in the nonvolatile memory, and the CPU and the DSP are used to realize the respective functions. Is a program module executed by The mute threshold table 57 is provided in the nonvolatile memory, and the mute register 58 and the channel selection frequency register 59 are provided in the working memory.

The broadcast receiver 50 includes a low noise amplifier 51, a variable frequency oscillator 52, a mixer 53, a detector 54, and a level detector 55.
The broadcast receiving unit 50 may be an IC chip in which these circuits are formed, for example. Many types of such IC chips are supplied as broadcast reception front-end ICs, and can be used as appropriate.
<Appearance>
FIG. 2 is a perspective view showing the appearance of the mobile phone 1. As illustrated, the mobile phone 1 is a foldable mobile phone in which an upper housing 2 and a lower housing 3 are connected. 2, the same components as those in FIG. 1 are denoted by the same reference numerals.

The display unit 84 is realized by a color liquid crystal panel, DMD (digital mirror device), organic EL panel, PDP (plasma display panel), or the like, and displays the current time, the remaining battery level, the radio wave intensity, and the like.
The operation unit 85 includes a numeric keypad 851, an off-hook key 852, an on-hook key 853, a direction key 854, and the like, and accepts a call start operation, dial operation, call end operation, channel selection operation, shooting mode start operation, shutter operation, and the like from the user. .

The image sensor 60 is, for example, a CCD (Charge Coupled Device) type or MOS (Metal Oxide Semiconductor) type solid-state image sensor. The image sensor 60 is built in the upper casing 2 and performs imaging through an opening provided on the back side of the upper casing 2 in the drawing. The memory card 86 is removably attached to the right side surface of the lower housing 3 in the drawing.
Although not shown, a circuit board on which the broadcast receiving unit 50, the camera front end unit 61, the baseband processing unit 40, and the like are mounted, and a speaker 83 are built in the lower housing 3.

Here, the mobile phone 1 is exemplified as a foldable mobile phone, but of course, it can also be realized as a straight mobile phone.
<Basic functions>
With reference to FIG. 1 again, the basic functions of the mobile phone 1 will be described.
<Call function>
The call function is realized as follows.

The duplexer 11 separates and mixes the speech frequency band signal and the broadcast frequency band signal. The duplexer 12 separates and mixes the transmission signal and the reception signal in the speech frequency band.
The wireless reception unit 20 acquires a reception signal in the communication frequency band from the antenna 10 via the duplexers 11 and 12, and demodulates the acquired reception signal into a baseband reception signal. The baseband processing unit 40 acquires the baseband received signal via the A / D converter 41, and the communication processing unit 45 converts the acquired received signal into an audio signal or an information signal according to a multiplexing method. . Specifically, the digital audio signal is obtained by despreading processing in the CDMA (Code Division Multiple Access) system and by time slot processing in the TDMA (Time Division Multiple Access) system. The voice processing unit 46 decodes the digital voice signal into a received voice signal and generates a sound from the receiver 81.

The audio processing unit 46 encodes the transmission audio signal acquired from the microphone 82 into a digital audio signal, and the communication processing unit 45 converts the digital audio signal into a digital transmission signal in accordance with the multiplexing method, and D / The A converter 44 converts the digital transmission signal into a baseband transmission signal.
The wireless transmission unit 30 modulates the baseband transmission signal into a communication frequency band transmission signal. The power amplifier 31 amplifies the transmission signal to a transmission level, and the amplified transmission signal is transmitted from the antenna 10 via the duplexers 12 and 11.

<Broadcast reception function>
The broadcast receiving function is realized as follows.
The broadcast receiving unit 50 acquires a reception signal in the broadcast frequency band from the antenna 10 via the duplexer 11. The variable frequency oscillator 52 is configured by using, for example, a PLL (Phase Locked Loop) circuit, and generates a local signal having a frequency indicated by a channel selection command given from the broadcast reception processing unit 56 according to the content of the channel selection frequency register 59. To do. The contents of the channel selection frequency register 59 are updated according to the user's channel selection operation.

The mixer 53 converts the reception signal amplified by the low noise amplifier 51 into a reception signal in the intermediate frequency band using the local signal. The detector 54 detects a received signal in the intermediate frequency band and outputs a broadcast signal, and the level detector 55 outputs a level signal indicating the strength of the received signal.
The broadcast reception processing unit 56 acquires the broadcast signal and the level signal via the A / D converters 42 and 43. Then, the acquired broadcast signal is converted into a baseband broadcast audio signal and is generated from the speaker 83 via the audio processing unit 46. Further, it is determined whether or not mute is necessary by referring to the acquired level signal and the contents of the mute threshold table 57, and the determination result is recorded in the mute register 58, and a mute command is issued according to the contents of the mute register 58. To the detector 54 to stop the output of the broadcast signal.

This mute process will be described in detail later.
<Shooting function>
The photographing function is realized as follows.
The camera front end unit 61 generates a camera clock and receives the camera control signal indicating the end of the shooting mode after receiving the camera control signal indicating the start of the shooting mode from the control unit 70 and supplies the camera clock to the image sensor 60. Supply.

  The image sensor 60 operates in response to the camera clock, and outputs a pixel signal representing a captured image in synchronization with the camera clock. The camera front end unit 61 generates an image signal of a predetermined format such as YUV or JPEG (Joint Picture Expert Group) from the pixel signal, and outputs the image signal to the control unit 70. The control unit 70 displays an image represented by the image information on the display unit 84.

The control unit 70 records the image on the memory card 86 in accordance with the user's shutter operation. During this recording, a memory card clock different from the camera clock is generated and supplied to the memory card 86.
<Mute control>
Next, the mute control will be described in detail.

<Mute threshold table>
FIG. 3 shows an example of the contents of the mute threshold value table 57. The mute threshold value table 57 stores in advance a plurality of frequencies included in the broadcast frequency band, threshold values corresponding to each frequency, camera offset, and memory card offset.
For example, the frequency is a value in increments of 0.1 MHz from 76.0 MHz to 108.0 MHz, which is a frequency band for FM broadcasting in Japan.

  The threshold indicates a minimum received signal level that does not mute the broadcast sound at the corresponding frequency in a state where all the clocks related to the additional function are stopped. This value is represented by a quantization value (hereinafter referred to as a level value) by the A / D converter 43 of the received signal level. When the A / D conversion is performed with 4 bits, the level value takes a value from 0 to 15. For example, broadcasting at 80.0 MHz is muted if the level value is less than 7 and audio is output if it is 7 or more in a state where all the clocks are stopped.

The camera offset is a value added to the threshold during the camera clock operation period. For example, a broadcast at 80.0 MHz is muted if the level value is less than 13 during the operation period of the camera clock, and is output if the level value is 13 or more.
The memory card offset is a value added to the threshold during the operation period of the memory card clock. For example, the threshold value at 80.0 MHz is increased by 2 during the operation period of the memory card clock.

The contents of the mute threshold table 57 are determined as follows, for example, based on the actual measurement of the noise level.
First, in a state where all the clocks related to the additional function are stopped, the noise level for each frequency is measured, and the measured noise level is set as the reference noise level. A value obtained by adding 1 or 2 to the reference noise level is set as a threshold value. Any noise that occurs regularly is taken into account at this reference noise level.

Next, in a state where one clock related to the additional function is operated, a noise level for each frequency is measured, and an increment from the reference noise level is set as an offset for the clock. The offset represents the noise level specific to that clock. This process is performed for each clock to determine an offset for each clock.
FIG. 4 is a graph showing measured noise (thin line) during camera clock operation and a value obtained by adding a camera offset to a threshold value (thick line) for each frequency. Here, specifically, two types of clocks of 13.75 MHz and 16.0 MHz are simultaneously generated as camera clocks, and the peak level values near 80.0 MHz, 82.5 MHz, 96.0 MHz, and 96.25 MHz are as follows: Both are due to the harmonics of the camera clock.

For example, the threshold value at 80.0 MHz is determined to be 7 based on the reference noise level (not shown) measured in advance, and the camera offset is based on the increment of the actually measured noise during the camera clock operation from the reference noise level. +6.
<Details of mute control processing>
FIG. 5 is a flowchart showing details of the mute control process.

This process is repeatedly executed during broadcast reception using the work variable t (S11 to S23).
The A / D converter 43 acquires the level signal and converts it into a level value (S12).
The broadcast reception processing unit 56 refers to the threshold value corresponding to the frequency held in the tuning frequency register 59 from the mute threshold value table 57, and sets t as the threshold value (S13).

  If the camera clock is operating (S14: YES), the camera offset is added to t (S15). If the memory card clock is operating (S16: YES), the memory card offset is added to t (S17). The operating state of the clock may be managed by the control unit 70, for example. In this case, whether or not the clock is operating can be determined by inquiring the control unit 70. A threshold value t taking into account the offset is set by the processing up to each.

Thereafter, t is compared with the level value. If the level value is equal to or greater than t (S18: YES), if the content of the mute register 58 is “ON” indicating that the mute is operating (S19: YES), “OFF The output of the mute command is stopped (S20). If the level value is less than the threshold value (S18: NO), if the content of the mute register 58 is “OFF” indicating that mute is being released (S21: YES), it is changed to “ON” and the mute command is issued. Output is started (S20).
<Summary>
As described above, the mute control technique of the present invention is applied to the broadcast receiving function in a mobile phone having a plurality of additional functions, manages the mute threshold value for each frequency, and particularly relates to each additional function. At the frequency point affected by the clock, the threshold during operation of the clock is set higher than the threshold during stop, so that normal listening is possible while the clock is stopped, and during operation Noise due to the clock can be reliably muted. Thereby, a favorable feeling of use is provided to the user.

  In the above description, the camera clock and the memory card clock are given as examples of noise for broadcast reception. However, a clock generator that generates other clocks (for example, a liquid crystal display, a USB (Universal Serial Bus), a voice, etc. A clock generator for a recorder) and a local oscillator for wirelessly transmitting and receiving communication and communication information can also be noise sources. Even in such a case, an appropriate mute control can be performed by providing an offset in the same manner for each noise source.

For the frequency at which noise constantly appears, the threshold value itself may be set higher than the threshold values of other frequencies.
<Other variations>
Although the present invention has been described based on the above embodiment, it is needless to say that the present invention is not limited to the above embodiment. The following cases are also included in the present invention.

A configuration and a method for searching for a station using the mute necessity determination described in the embodiment are also included in the present invention. The station search configuration is a configuration for sequentially increasing or decreasing the frequency held in the channel selection frequency register 59 until it is determined that mute is unnecessary.
This configuration can be easily obtained only by changing the software when the broadcast reception processing unit 56 is realized as a software function, and particularly requires additions and changes related to hardware from the configuration shown in FIG. And not.

FIG. 6 is a flowchart showing details of the station search process executed by the broadcast reception processing unit 56.
This process is repeatedly executed while sequentially changing the tuning frequency (S31 to S39). The process (S32 to S38) for determining whether mute is necessary for the current channel selection frequency is the same as the process described in the embodiment (S12 to S18 in FIG. 5). If the level value is greater than or equal to t (S38: YES), the process repeats and the broadcast is received at the current channel selection frequency (S40).

With this configuration, it is possible to reliably avoid the inconvenience that the normal search is performed while the clock related to the additional function is stopped and the search is stopped due to the noise of the clock during the operation.
The present invention may be a computer program for executing the steps described in the embodiment using a CPU for controlling a mobile phone, or may be a digital signal representing the program.

Further, the present invention may be a computer-readable recording medium in which the program or the digital signal is recorded, for example, a flexible disk, a hard disk, a CD, an MO, a DVD, a BD, a semiconductor memory, or the like.
The present invention may be the computer program or the digital signal transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, or the like.

  The program or the digital signal may be recorded on the recording medium and transferred, or may be transferred via the network or the like and executed on another independent mobile phone.

  The mobile phone according to the present invention can be used as a multi-function mobile phone having a broadcast receiving function.

It is a functional block diagram which shows the whole structure of the mobile telephone which concerns on this Embodiment. It is a perspective view which shows the external appearance of the said mobile phone. It is an example of the content of a mute threshold value table. It is a graph which shows the relationship between measured noise and a threshold value. It is a flowchart which shows a mute control process. It is a flowchart which shows a broadcast station search process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cellular phone 2 Upper housing | casing 3 Lower housing | casing 10 Antenna 11, 12 Duplexer 20 Wireless receiving part 30 Wireless transmitting part 31 Power amplifier 40 Baseband process part 41-43 A / D converter 44 D / A converter 45 Communication processing part 46 Audio processing unit 50 Broadcast reception unit 51 Low noise amplifier 52 Variable frequency oscillator 53 Mixer 54 Detection unit 55 Level detection unit 56 Broadcast reception processing unit 57 Value table 58 Mute register 59 Tuning frequency register 60 Image sensor 61 Camera front end unit 62 Image processing Unit 70 Control unit 81 Receiver 82 Microphone 83 Speaker 84 Display unit 85 Operation unit 86 Memory card 851 Numeric keypad 852 Off-hook key 853 On-hook key 854 Direction key

Claims (11)

A mobile phone having a broadcast receiving function for receiving broadcast and muting broadcast audio according to a received signal level,
A noise source that intermittently generates noise included in the frequency band used for the broadcast;
Setting means for setting a first threshold value during the noise stop period and setting a second threshold value larger than the first threshold value during the noise generation period;
And a mute means for muting the broadcast audio when the received signal level is less than the set threshold value. The setting means sets a first threshold value and a second threshold value for each of a plurality of frequencies included in the frequency band used for the broadcast,
It said muting means, the cellular telephone of claim 1, when the received signal level in the current channel selection frequency is less than the threshold value set for the tuning frequency, characterized by muting the broadcast audio. The mobile phone according to claim 2, wherein the setting unit sets, for each frequency, a value obtained by adding the noise level at the frequency to a first threshold value as a second threshold value. . The mobile phone further includes:
A station search means for comparing the received signal level at the current channel selection frequency with a threshold value set for the channel selection frequency and sequentially changing the current channel selection frequency until a predetermined comparison result is obtained; The mobile phone according to claim 2 or 3, characterized in that The noise source includes a local oscillator for wireless communication, and a clock generator for driving at least one of a camera unit, a liquid crystal display, a memory card, a USB (Universal Serial Bus), and a voice recorder provided in the mobile phone. The mobile phone according to claim 1, wherein: A method for controlling a mobile phone having a broadcast receiving function for receiving broadcast and muting broadcast audio in accordance with a received signal level, wherein the mobile phone generates noise included intermittently in a frequency band used for the broadcast With a source,
A setting step of setting a first threshold value during the noise stop period and setting a second threshold value larger than the first threshold value during the noise generation period;
And a mute step of muting the broadcast audio when the received signal level is less than the set threshold value. The setting step sets a first threshold value and a second threshold value for each of a plurality of frequencies included in the frequency band used for the broadcast,
The muting step The control method of claim 6, when the received signal level in the current channel selection frequency is less than the threshold value set for the tuning frequency, characterized by muting the broadcast audio. The control method according to claim 7, wherein the setting step sets, for each frequency, a value obtained by adding a noise level at the frequency to the first threshold value as the second threshold value. The control method further includes:
A station search step of comparing the received signal level at the current channel selection frequency with a threshold set for the channel selection frequency and sequentially changing the current channel selection frequency until a predetermined comparison result is obtained. The control method according to claim 7 or 8, wherein the control method is characterized. A computer-executable program for controlling a mobile phone having a broadcast receiving function for receiving broadcast and muting broadcast audio according to the received signal level,
The mobile phone includes a noise source that intermittently generates noise included in a frequency band used for the broadcasting,
A program that causes a computer to execute the steps according to at least one of claims 6 to 9. The noise source intermittently generates noise of a predetermined frequency,
The setting means sets a first threshold value during the noise stop period at the predetermined frequency, and sets a second threshold value larger than the first threshold value during the noise generation period. It is characterized by setting a threshold
The mobile phone according to claim 1.

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