WO2010100889A1

WO2010100889A1 - Digital broadcast receiving device and digital broadcast receiving method

Info

Publication number: WO2010100889A1
Application number: PCT/JP2010/001391
Authority: WO
Inventors: 鈴木英治; 浜田勝浩
Original assignee: パナソニック株式会社
Priority date: 2009-03-03
Filing date: 2010-03-02
Publication date: 2010-09-10
Also published as: JP2012104863A

Abstract

A digital broadcast receiving device is provide with N built-in antennas, N tuners, N power switches, a carrier synthesis unit for synthesizing a plurality of individual carrier signals, and a demodulation unit for demodulating a video/audio signal from the carrier signal. A CPU selects a tuner used for demodulation on the basis of the results of detections by individual carrier C/N detectors and a synthesized carrier C/N detection unit and controls the N power switches such that the power is supplied to the selected tuner and the supply of power to the tuners not selected is stopped.

Description

Digital broadcast receiving apparatus and digital broadcast receiving method

The present invention relates to a portable digital broadcast receiving apparatus and a digital broadcast receiving method capable of performing stable broadcast signal reception by a diversity reception function using a plurality of antennas.

2. Description of the Related Art Portable portable television broadcast receivers have been widely used. However, since the broadcast radio wave is received by the rod antenna attached to the receiving device, it is difficult to obtain a sufficient received signal strength as compared with the case of receiving by a fixed antenna installed outdoors.

Therefore, noise is likely to be displayed on the screen in a conventional portable small television broadcast receiver. Further, in a conventional portable small television broadcast receiving apparatus, a ghost is likely to occur on the screen due to the influence of reflected waves.

In other words, the conventional portable small television broadcast receiver has a problem in reproduction video quality.

However, in recent years, the problem has been solved by digital broadcasting. For example, in Japan's terrestrial digital broadcasting, a modulation method called OFDM (Orthogonal Frequency Division Multiplex) is used. This modulation method is advantageous in the environment of multiple reflection propagation (multipath), and therefore has a feature that the transmission error rate can be suppressed low.

There is also a technique called diversity reception that can improve the reception strength of radio waves. Diversity reception is a technique for receiving broadcast radio waves with a plurality of antennas with different reception conditions.

By selecting the antenna with the best reception state among the plurality of antennas used for diversity reception, the reception quality can be improved as compared with the case of receiving with one antenna. Alternatively, the reception quality can be improved by combining received radio waves from a plurality of antennas as compared with the case of reception by a single antenna.

The reception quality can be improved more effectively by combining this diversity reception and OFDM.

That is, instead of simply selecting the antenna with the best reception state by diversity reception, the reception quality can be greatly improved by combining the plurality of radio waves having different reception levels and delay characteristics most efficiently received from each antenna. . Diversity reception is practically used frequently in in-vehicle digital broadcast receivers that are expected to have a very poor reception environment.

As mentioned above, diversity reception is very effective for receiving digital broadcasts using OFDM modulation. Furthermore, many improvement proposals have been made to enhance the effect. In the proposal, for example, there is a method of individually adjusting the characteristics of each tuner installed immediately after the antenna, instead of simply synthesizing the received radio waves from each antenna as they are. In this way, the synthesis effect can be further enhanced.

Tuner characteristic adjustment methods include, for example, gain adjustment and setting of a time constant for level detection used when gain is automatically controlled (see, for example, Patent Document 1).

As described above, diversity reception is an extremely effective reception method for a portable digital broadcast receiver. However, the power consumption of the receiving device is relatively high. This is because, in diversity reception, received radio waves from a plurality of antennas are simultaneously input and combined.

That is, if a plurality of tuner units are simultaneously operated in the receiving apparatus, and the radio waves from each antenna are amplified and a desired channel is selected, the power consumption increases. Moreover, as is well known, a tuner unit in a television broadcast receiving apparatus needs to amplify the UHF band up to 770 MHz. Therefore, the amount of current flowing through the semiconductor element to be used is increased, and it is usually difficult to achieve power saving because it is composed of an analog circuit. In recent years, reduction of power consumption of electrical products has been strongly demanded from the standpoint of environmental protection. Therefore, it is not preferable that power consumption increases due to diversity reception.

In addition, the convenience of the user is further improved if it can be driven using a battery as a portable or portable product. However, if power consumption increases due to diversity reception, this battery drive It will conflict.

JP 2006-319608 A

A digital broadcast receiver according to the present invention includes N (N is a natural number of 2 or more) built-in antennas, an external antenna, an antenna input switching unit, N tuner units, N power switch units, A carrier synthesis unit, a demodulation unit, a quality evaluation value detection unit, and a control unit are provided.

N built-in antennas (N is a natural number of 2 or more) receive digital broadcast waves. The external antenna receives a digital broadcast wave. The antenna input switching unit switches between an input from any one of the N built-in antennas and an input from an external antenna. The N tuner units are connected to the built-in antenna and the antenna input switching unit, and output individual carrier signals having a frequency corresponding to a predetermined broadcast channel. The N power switch units supply power to each of the N tuner units. The carrier combining unit outputs a combined carrier signal obtained by combining individual carrier signals output from two or more tuner units among the N tuner units.

The demodulator demodulates the video / audio signal from the individual carrier signal or the synthesized carrier signal. The carrier quality evaluation value detection unit detects the quality evaluation value of the individual carrier signal or the combined carrier signal. The control unit selects a predetermined number of tuner units used for demodulation based on at least one of the detection result of the carrier quality evaluation value detection unit and the antenna input switching information of the antenna input switching unit, and is selected by the power switch unit. Only a predetermined number of tuner units are supplied with power.

In such a configuration, compared to normal diversity reception, not all antennas are used, but the antenna to be used is determined according to the quality of the carrier signal, and a predetermined number of tuner units connected to this antenna are assigned. Only supply power. As a result, power consumption can be reduced.

The digital broadcast receiving method of the present invention is a digital broadcast reception in a digital broadcast receiving apparatus including N (N is a natural number of 2 or more) built-in antennas for receiving digital broadcast waves and an external antenna for receiving digital broadcast waves. A method of supplying power only to a tuner unit connected to an external antenna; detecting a quality evaluation value of an individual carrier signal of the tuner unit connected to the external antenna; and When the quality evaluation value of the individual carrier signal of the connected tuner unit is equal to or higher than the predetermined reference value, the tuning operation is performed with the tuner unit connected to the external antenna. A step of supplying power to the tuner unit connected to the antenna and a tuner connected to the built-in antenna The step of detecting the quality evaluation value of the individual carrier signal of the unit, and if the quality evaluation value of the individual carrier signal of the tuner unit connected to the detected built-in antenna is equal to or higher than a predetermined reference value, The tuning operation is performed only with the tuner unit having the best quality evaluation value, and the power supply to the tuner units other than the tuner unit is stopped. When the tuner unit is less than a predetermined reference value, Performing a tuning operation.

FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to

Embodiments

1, 2, and 3 of the present invention. FIG. 2 is a specific configuration diagram of the video / audio decoder unit in the first, second, and third embodiments. FIG. 3 is a flowchart showing a processing procedure of diversity reception control in Embodiment 1 of the present invention. FIG. 4 is a flowchart showing another example of the processing procedure of diversity reception control in Embodiment 1 of the present invention. FIG. 5 is a flowchart showing a processing procedure of diversity reception control in Embodiment 2 of the present invention. FIG. 6A is a flowchart showing a processing procedure of diversity reception control in Embodiment 3 of the present invention. FIG. 6B is a flowchart showing a processing procedure of diversity reception control in Embodiment 3 of the present invention. FIG. 6C is a flowchart showing a processing procedure of diversity reception control in Embodiment 3 of the present invention. FIG. 7 is a flowchart showing a processing procedure of diversity reception control in Embodiment 4 of the present invention. FIG. 8 is a flowchart showing another example of the processing procedure of diversity reception control in Embodiment 4 of the present invention. FIG. 9 is a flowchart showing a processing procedure of diversity reception control in Embodiment 5 of the present invention. FIG. 10 is a diagram showing an example of a control table in Embodiment 5 of the present invention.

(Embodiment 1)
Hereinafter, a digital broadcast receiving apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the digital broadcast receiving apparatus includes N built-in antennas 100 (1) to 100 (N), N tuner units 170 (1) to 170 (N), a carrier combining unit 201, Demodulation section 202, video / audio decoder section 203, combined carrier C / N detection section 204 as a combined carrier quality evaluation value detection section, CPU (Central Processing Unit) 205 as a control section, system bus 206, storage A RAM (Random Access Memory) 207, an external antenna connection terminal 121, and an antenna input switching unit 122 are provided.

The tuner unit 170 (1) includes a tuner unit 130 (1), a carrier switch unit 140 (1), an individual carrier C / N detection unit 150 (1) as an individual carrier quality evaluation value detection unit, and a power switch. Part 160 (1). The other tuner units 170 (2) to 170 (N) have the same configuration.

Broadcast radio waves received by the N built-in antennas 100 (1) to 100 (N) are input to the tuner units 130 (1) to 130 (N), respectively. Built-in antennas 100 (1) to 100 (N) are prepared for diversity reception. The built-in antennas 100 (1) to 100 (N) are arranged at appropriate intervals in the digital broadcast receiving apparatus, and are often installed with different directivities.

Tuner units 130 (1) to 130 (N) amplify received broadcast radio waves. Further, tuner units 130 (1) to 130 (N) selectively pick out a desired broadcast channel based on the result of channel selection by the user, and a carrier signal of a predetermined frequency after channel selection (hereinafter simply referred to as “carrier”). (Also called). In general, the predetermined frequency is set to a so-called intermediate frequency in consideration of ease of processing in a later stage. Further, the specific value of N, which is the number of the predetermined number of tuner units used for demodulation, is determined in consideration of the price of the product and the like, but about 2 to 4 are preferable for practical use.

Here, as shown in FIG. 1, in addition to the built-in antenna 100 (N), an external antenna connection terminal 121 is prepared for the Nth tuner unit 130 (N) so that the external antenna 110 can be connected.

The antenna input switching unit 122 switches between the built-in antenna 100 (N) and the external antenna 110 to be used as the input of the tuner unit 130 (N). This switching operation may be performed electronically by the user with the remote control or the main body operation unit with respect to the digital broadcast receiving apparatus. For simplicity, a mechanical switch mechanism is provided in the antenna input switching unit 122 so that the user can It may be switched manually and mechanically.

Since the external antenna 110 is usually installed on the roof of a house or on the roof of a building, it has an excellent reception environment and can receive a stable broadcast wave compared to the built-in antennas 100 (1) to 100 (N). If the user subscribes to CATV (cable TV), it is possible to connect a CATV lead-in line to the external antenna connection terminal 121.

The output carriers of the tuner units 130 (1) to 130 (N) are input to the carrier switch units 140 (1) to 140 (N), respectively. Carrier switch sections 140 (1) to 140 (N) are provided to control whether or not the output carrier from each tuner section is used for diversity combining. The carrier switch sections 140 (1) to 140 (N) have a function as a high frequency switch for conducting and blocking carriers.

The output carriers of the tuner units 130 (1) to 130 (N) are also input to the individual carrier C / N detection units 150 (1) to 150 (N), respectively. Whether individual carrier C / N detectors 150 (1) to 150 (N) have sufficient quality for receiving digital broadcasts for the output carriers from the respective tuner units 130 (1) to 130 (N) Is evaluated by detecting the CNR (Carrier to Noise Ratio: hereinafter referred to as “C / N”) of the output carrier.

Specifically, the CPU 205 makes a determination by comparing with a predetermined reference value set in advance. Here, the predetermined reference value is a required C / N ratio that is a C / N ratio at which the occurrence of an error is sufficiently small so that a broadcast wave can be normally received. For example, in Japanese terrestrial digital broadcasting, when the received signal is a 64QAM (Quadrature Amplitude Modulation) modulation method and the coding rate is 7/8, the predetermined reference value may be about 22 dB. The parameter for evaluating the quality of the carrier may simply be the signal strength of each carrier.

The individual carriers output from the N carrier switch units 140 (1) to 140 (N) included in the tuner units 170 (1) to 170 (N) are input to the carrier combining unit 201 and are combined (carrier addition). The

The synthesized carrier output from the carrier synthesizing unit 201 is extracted as a video signal 208 and an audio signal 209 via the demodulating unit 202 and the video / audio decoder unit 203.

The demodulating unit 202 performs an operation of demodulating a carrier of a digitally modulated broadcast signal. The digital modulation used for digital broadcasting, for example, multi-level QAM ((High-Order) Quadrature Amplitude Modulation) or OFDM is used. Demodulate.

Also, the video / audio decoder unit 203 performs processing for reproducing the demodulated data demodulated by the demodulating unit 202 into a bit stream into a video / audio signal.

FIG. 2 shows a specific configuration example of the video / audio decoder unit 203. As shown in FIG. 2, the bit stream input from the demodulator 202 is first required from the TS signal by the TS (Transport Stream) decoder unit 232 after the transmission error at the time of broadcast reception is corrected by the error correction unit 231. Video and audio information is extracted.

Finally, the AV decoder unit 233 performs decoding of the compressed data such as MPEG (Moving Picture Experts Group) 2 and D / A conversion as necessary, and converts it into an externally usable signal form and outputs it. Here, as an example of the signal form, a video signal 208 and an audio signal 209 are output.

As shown in FIG. 1, the synthesized carrier synthesized by the carrier synthesizing unit 201 is also input to the synthesized carrier C / N detecting unit 204. The composite carrier C / N detection unit 204 detects the C / N of the composite carrier. The detected composite carrier C / N is taken into the CPU 205 and evaluated whether or not it has a quality sufficient for receiving digital broadcasting. The evaluation is the same as that of the individual carrier C / N detectors 150 (1) to 150 (N), and is performed by comparing the combined carrier C / N with a predetermined reference value determined in advance.

The CPU 205 acquires detection results of the individual carrier C / N detection units 150 (1) to 150 (N) and the combined carrier C / N detection unit 204. Subsequently, the CPU 205 determines an antenna and a tuner unit to be used for diversity reception, and controls power supply to each of the tuner units 170 (1) to 170 (N). Each tuner unit 170 (1) to 170 (N) is provided with a power switch unit 160 (1) to 160 (N), respectively. Each tuner unit 170 (1) to 170 (N) receives control from the CPU 205 via the system bus 206, and supplies (ON) or stops (OFF) power to the corresponding tuner unit.

This mechanism allows power to be supplied only to the necessary tuner units, thereby reducing the power consumption of the digital broadcast receiver.

The tuner units 130 (1) to 130 (N), the carrier switch units 140 (1) to 140 (N), and the individual carrier C / N detection unit 150 (in each tuner unit 170 (1) to 170 (N). 1) to 150 (N) and the power supply switch sections 160 (1) to 160 (N) are all supplied with control signals from the system bus 206.

In addition, tuner units 130 (1) to 130 (N), carrier switch units 140 (1) to 140 (N), and individual carrier C / N detection units 150 (1) in each of the tuner units 170 (1) to 170 (N). ) To 150 (N) and the power switch units 160 (1) to 160 (N) send internal information to the system bus 206.

In FIG. 1, for the sake of convenience, control lines are not individually entered for each, but one control line is entered for the entire tuner unit.

Next, the operation of the digital broadcast receiving apparatus according to the embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a flowchart showing a processing procedure of diversity reception control in Embodiment 1 of the present invention.

First, in step S101, the CPU 205 performs the antenna input switching unit 122 through a series of channel selection operations of the digital broadcast receiving device such as channel selection by a user channel selection operation, channel selection by reservation execution, and channel selection for program information storage. Read the setting status.

When the user electronically sets the digital broadcast receiving apparatus with the remote controller or the main body operation unit, the CPU 205 reads the contents of a storage unit (not shown) such as a nonvolatile memory in which the setting value is stored. become.

When a mechanical switch mechanism is attached to the antenna input switching unit 122 and the user performs a mechanical switching operation manually, the CPU 205 can detect the mechanical position to detect the antenna selection setting.

If it is detected in step S101 that the external antenna 110 is set, the antenna input switching unit 122 selects an input from the external antenna 110 in step S102 and uses an input signal from the external antenna 110 for demodulation. .

When the external antenna 110 is connected, the antenna input switching unit 122 always selects an external input from the external antenna 110. In this way, only the Nth tuner unit 170 (N) needs to operate among the tuner units 170 (1) to 170 (N).

Therefore, in response to an instruction from the CPU 205, the power switch units 160 (1) to 160 (N) turn off the power of the tuner units 170 (1) to 170 (N-1) other than the Nth in step S103. Subsequently, the power switch units 160 (1) to 160 (N) turn on the power of the Nth tuner unit 170 (N) in step S104.

Next, in step S105, the CPU 205 turns on only the carrier switch unit 140 (N) of the Nth tuner unit 170 (N) and sets the carrier synthesis unit 201 to a non-synthesis setting. In this case, only the output carrier from tuner unit 170 (N) is used for demodulation by demodulation section 202.

When the power switch units 160 (1) to 160 (N) and the carrier switch units 140 (1) to 140 (N) are subjected to predetermined control, a channel selection process is performed in step S106, and a reception process for a desired broadcast channel is performed. Be started.

Specifically, the operations of the demodulation unit 202 and the video / audio decoder unit 203 are started. Note that the channel selection processing here includes not only channel selection but also processing for changing various parameters (such as filter constants) of the tuner units 130 (1) to 130 (N).

On the other hand, when it is detected in step S101 that the built-in antenna is set, the antenna input switching unit 122 selects an input from the built-in antenna 100 (N) in step S112.

When receiving only with the built-in antenna, normal diversity reception (reception using all the built-in antennas) is performed, and in response to an instruction from the CPU 205 in step S113, the power switch sections 160 (1) to 160 ( N) turns on all the tuner units 170 (1) to 170 (N).

Thereafter, in step S114, the CPU 205 turns on all the carrier switch units 140 (1) to 140 (N) and sets the carrier combining unit 201 to combine all carriers.

After the above control is completed, the reception process of the desired broadcast channel is started by the channel selection process in step S106, and the process ends.

The method shown in FIG. 4 is almost the same as the above processing flow, but it is determined whether the external antenna 110 is connected to the external antenna connection terminal 121 instead of setting the antenna input selection by the user setting information. Then, diversity reception control is performed.

That is, the method shown in FIG. 4 automatically detects whether an input signal from the external antenna 110 is input, and performs diversity reception control using the detection result. In step S121 in FIG. 4, if the external antenna connection terminal 121 has an external antenna connection, the process proceeds to step S102, and if there is no external antenna connection, the process proceeds to step S112. The subsequent processing flow is the same as in FIG.

As described above, according to the digital broadcast receiving apparatus in the embodiment of the present invention, when there is an external antenna connection, diversity reception by the built-in antenna is not performed, and only the input signal from the external antenna 110 is used for demodulation. .

Therefore, the power of the tuner unit other than the tuner unit connected to the external antenna can be turned off, so that the power consumption can be reduced and the input signal from the external antenna 110 is used, so that stable reception is possible. Become.

Furthermore, since the digital broadcast receiving apparatus according to the present embodiment automatically selects an external antenna only when there is an input signal from the external antenna 110, the user does not need to perform an input switching operation.

In addition, the digital broadcast receiving apparatus according to the embodiment of the present invention does not erroneously select the external antenna even though there is no input signal from the external antenna 110.

(Embodiment 2)
Next, a digital broadcast receiving apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing a processing procedure of diversity reception control in Embodiment 2 of the present invention.

The digital broadcast receiving apparatus according to the present embodiment first checks whether sufficient reception quality can be obtained only with the external antenna, and receives with the external antenna if sufficient reception quality is obtained.

The digital broadcast receiving apparatus according to the embodiment of the present invention investigates whether any one of the built-in antennas cannot provide sufficient quality if the reception quality is insufficient. If sufficient reception quality is obtained, the signal is received by this built-in antenna, and if it is not sufficient, normal diversity reception by all built-in antennas is performed.

First, in step S202, the antenna input switching unit 122 selects an input signal from the external antenna 110 as an input of the Nth tuner unit 170 (N). In step S203, in response to an instruction from the CPU 205, the power switch units 160 (1) to 160 (N-1) turn off the power of the tuner units 170 (1) to 170 (N-1). In step S204, in response to an instruction from the CPU 205, the power switch unit 160 (N) turns on the power of the Nth tuner unit 170 (N).

Subsequently, in step S205, the CPU 205 turns on only the carrier switch unit 140 (N) of the Nth tuner unit 170 (N) and sets the carrier combining unit 201 to non-combining, and outputs the carrier from the tuner unit 170 (N). Are used in the demodulator 202.

Then, in step S206, channel selection processing is performed. In step S207, the individual carrier C / N detection unit 150 (N) detects the individual carrier C / N of the Nth tuner unit 170 (N). If the detected individual carrier C / N is equal to or greater than a predetermined reference value, broadcast reception is started and the process is terminated.

If the individual carrier C / N detected in step S207 described above does not reach the predetermined reference value, in step S211, the antenna input switching unit 122 uses the built-in antenna 100 (N) as the antenna input of the Nth tuner unit 170 (N). ) Is selected.

In step S212, upon receiving an instruction from the CPU 205, the power switch units 160 (1) to 160 (N) turn on the power to all the tuner units 170 (1) to 170 (N-1) (tuner unit 170 ( N) is already turned on in step S104).

Next, after performing a channel selection process in step S213, the individual carrier C / N detection units 150 (1) to 150 (N) of the tuner units 170 (1) to 170 (N) are switched to the individual carrier C in step S214. / N is detected, and it is investigated whether any one satisfies the predetermined reference value.

If there is even one satisfying the predetermined reference value, the process proceeds to step S215, and the power switch 160 (1) is set so that the tuner unit other than the tuner unit for which the CPU 205 obtains the best C / N is turned off. ) To 160 (N).

In step S216, the CPU 205 controls the carrier switch units 140 (1) to 140 (N) to turn on only the carrier switch of the tuner unit that obtains the best C / N, and sets the carrier synthesis unit 201 to non-synthesis. Thereafter, broadcast reception is started and the process is terminated.

On the other hand, if each of the individual carriers C / N is less than the predetermined reference value in step S214, the process proceeds to step S221, and the CPU 205 turns on the carrier switch units 140 (1) to 140 (N) and sets the carrier combining unit. 201 is set to synthesize the output carriers of all tuner units 170 (1) to 170 (N).

Thereafter, the process proceeds to step S222, the channel selection process is executed again, the various parameters of the tuner units 130 (1) to 130 (N) are tuned, broadcast reception is started, and the process is terminated. The RAM 207 performs an operation of temporarily storing the detected plurality of individual carriers C / N in order to select the best one from the plurality of individual carriers C / N.

As described above, according to the digital broadcast receiving apparatus in the present embodiment, normal diversity reception is performed when the detection value of the individual carrier C / N satisfies a predetermined reference value among the external antenna and all the built-in antennas. This is only when there is not one.

If there is at least one individual carrier C / N detection value that satisfies a predetermined reference value, power is supplied only to the tuner unit connected to the antenna, and the output carrier is used for demodulation. Then, all the power supplies of the tuner units connected to the other antennas are turned off. Therefore, according to the digital broadcast receiving apparatus in the present embodiment, it is possible to reduce power consumption as compared with normal diversity reception. .

(Embodiment 3)
Next, a digital broadcast receiving apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. 6A, 6B, and 6C. 6A, FIG. 6B, and FIG. 6C are flowcharts showing a diversity reception control processing procedure according to Embodiment 3 of the present invention. In the embodiment of the present invention, N, which is the number of tuner units, is set to 4 for convenience of explanation.

The digital broadcast receiving apparatus according to this embodiment is for receiving diversity by selecting two built-in antennas from the four built-in antennas. Similarly to the digital broadcast receiving apparatus in the second embodiment, a plurality of detected composite carriers C / N are temporarily stored in the RAM 207 in order to select the best one from the detected composite carriers C / N.

Steps S202 to S216 in FIG. 6A are the same processing as in FIG. 5 used in Embodiment 2 of the present invention.

That is, in steps S202 to S207, it is checked whether or not sufficient reception quality is obtained with the external antenna 110. If the individual carrier C / N is equal to or greater than a predetermined reference value, the tuner unit 170 (4) connected to the external antenna 110 is checked. ) Shows a process of supplying power only to starting broadcast reception.

If sufficient reception quality is not obtained with the external antenna 110 (when the individual carrier C / N is less than a predetermined reference value), sufficient reception quality is achieved with any one of the built-in antennas in steps S211 to S216. If the individual carrier C / N satisfies a predetermined reference value even with one built-in antenna, the tuner unit in which the individual carrier C / N is connected to the best built-in antenna. Supply power only to start broadcast reception. Then, the other tuner units are turned off.

If the individual carrier C / N does not exceed the predetermined reference value in any tuner unit in step S214, the digital broadcast receiving apparatus of the present embodiment proceeds to step S301 in FIG. 6B.

Steps S301 to S321 check whether the combined carrier C / N of the two built-in antennas out of the four built-in antennas exceeds a predetermined reference value, and if there is, the power is supplied to only the corresponding tuner unit. The operation to supply is realized.

There are six combinations for selecting two built-in antennas from four built-in antennas. For simplicity of explanation, the combination of built-in antennas 100 (1) and 100 (2) is selected, A description will be given focusing on two types in the case of selecting a combination of the antennas 100 (3) and 100 (4).

In step S301, upon receiving an instruction from the CPU 205, the power switch units 160 (3) and 160 (4) turn off the power of the tuner units 170 (3) and 170 (4).

Before entering step S301, all the tuner units 170 (1) to 170 (4) are powered on by the power switch units 160 (1) to 160 (4) receiving instructions from the CPU 205. Therefore, after S301, the tuner units 170 (1) and 170 (2) are in the power-on state.

In step S302, the CPU 205 turns on the carrier switch sections 140 (1) and 140 (2).

After the channel selection process in step S303, the carrier combining unit 201 combines only the output carriers of the tuner units 170 (1) and 170 (2).

In step S304, the composite carrier C / N detection unit 204 detects the composite carrier C / N (indicated as “C / N of composite carrier (1) + (2)” in FIG. 6B).

As a result of the detection in S304, if the composite carrier C / N exceeds a predetermined reference value, the numerical value of the detected composite carrier C / N is stored in the RAM 207 in step S305.

Next, in S306 to S311, for the tuner units 170 (3) and 170 (4), the same processing as that performed in S301 to S305 for the tuner units 170 (1) and 170 (2) is performed.

In step S310, the combined carrier C / N of tuner units 170 (3) and 170 (4) (shown as “C / N of combined carrier (3) + (4)” in FIG. 6C) also exceeds the predetermined reference value. If the CPU 205 determines that the combined carrier C / N is stored in the RAM 207 in step S311.

Next, in step S312, the two types of synthetic carrier C / N stored in the RAM 207 are read out and compared with the CPU 205, and the combination with the larger synthetic carrier C / N is selected.

If the combined carrier C / N of the tuner units 170 (3) and 170 (4) is larger than the combined carrier C / N of the tuner units 170 (1) and 170 (2), the tuner unit is already at that time. Power is supplied to 170 (3) and 170 (4), and the channel selection process is also completed. Therefore, the digital broadcast receiving apparatus immediately starts broadcast reception and ends the process.

Conversely, if the combined carrier C / N of tuner units 170 (1) and 170 (2) is larger than the combined carrier C / N of tuner units 170 (3) and 170 (4), steps S313 to S316 are performed. After the power switch and the carrier switch are controlled, the channel selection process is performed. Then, the digital broadcast receiving apparatus starts broadcast reception and ends the process.

On the other hand, if the combined carrier C / N of the tuner units 170 (1) and 170 (2) falls below a predetermined reference value in step S304, the CPU 205 performs steps S317 to S321 in which the tuner units 170 (3) and 170 It is checked whether the synthetic carrier C / N in (4) exceeds a predetermined reference value. In the case of exceeding, the digital broadcast receiving apparatus starts broadcast reception using the combined carrier of the tuner units 170 (3) and 170 (4) as it is, and ends the processing. When the combined carrier C / N of the tuner units 170 (3) and 170 (4) is also below a predetermined reference value, power is supplied to all the tuner units 170 (1) to 170 (4) through steps S401 to S403. . Using the composite carrier from tuner units 170 (1) to 170 (4), the digital broadcast receiving apparatus starts broadcast reception and ends the process.

As described above, according to the digital broadcast receiving apparatus of the present embodiment, when all of the four built-in antenna carriers C / N do not satisfy the predetermined reference value, the carriers of all four built-in antennas are combined. Instead of the following processing. First, a carrier is synthesized by a combination of two antennas. Next, if the combination carrier C / N of any combination satisfies a predetermined reference value, broadcast reception is performed with the combination carrier of that combination. Then, the power of the tuner unit connected to the other two built-in antennas is turned off. As a result, power consumption can be reduced as compared with normal diversity reception using all four antennas.

(Embodiment 4)
Next, a digital broadcast receiving apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 7 is a flowchart showing a processing procedure of diversity reception control in Embodiment 4 of the present invention.

For example, even if the status of received radio waves changes during broadcast reception, the digital broadcast receiver of this embodiment changes the diversity reception control method according to the status of the received radio waves, and always receives broadcasts stably. To do.

In FIG. 7, first, in step S <b> 501, the CPU 205 checks the user setting state of the antenna input switching unit 122. When the external antenna 110 is selected, the individual carrier C / N detection unit 150 (N) of the tuner unit 170 (N) to which the external antenna 110 is connected detects the individual carrier C / N in step S502.

If the built-in antenna is selected, in step S503, the CPU 205 determines whether power is supplied only to a single tuner unit or whether power is supplied to all tuner units 170 (1) to 170 (N). To detect.

If the power supply is a single tuner unit, the CPU 205 detects the individual carrier C / N of the corresponding tuner unit in step S504.

If all the tuner units 170 (1) to 170 (N) are supplied with power, the CPU 205 detects the combined carrier C / N in step S505.

If the individual carrier C / N or the combined carrier C / N exceeds a predetermined reference value, the process is terminated without performing any process, and after waiting for a certain time in step S507, the process returns to the beginning. , The process proceeds to S501.

On the other hand, if the individual carrier C / N or the combined carrier C / N of the tuner unit currently selected is below the predetermined reference value in step S502, S504, or step S505, the process moves to step S506, and the antenna Make a new selection.

Step S506 is a processing flow according to the flowchart of FIG. As described above, the diversity reception method through the process flow of FIG. 5 is a method for maintaining carrier quality in the order of using an external antenna, using one of the built-in antennas, and using all the built-in antennas. You can choose. Therefore, the digital broadcast receiving apparatus according to the present embodiment can recover the reception quality even when the radio wave condition changes.

FIG. 8 is a flowchart obtained by modifying a part of the flowchart of FIG.

The differences from the flowchart in Fig. 7 are described. Step S601 is processing for detecting the number of tuner units that are powered on, as in step S503 in FIG. However, in the case of FIG. 7, the number of power-on tuner units is one or all (N), whereas in FIG. 8, the number is one or more than two.

As shown in the flowchart of FIG. 6C cited in FIG. 8, the number of tuner units may be one or all (N), or may be M (M is 2 or more and less than N).

Therefore, step S603 includes not only the evaluation of the combined carrier by all the tuner units 170 (1) to 170 (N) as in step S505 in FIG. 7, but also the evaluation of the combined carrier by the M tuner units 170. Process.

Also, as a matter of course, the reception quality recovery step S604 after waiting for a certain period of time in preparation for the case where the radio wave condition has changed, also includes one or all of the tuner units as shown in FIGS. 6A, 6B, and 6C. (N) or M (M is 2 or more and less than N) may be performed.

That is, in the case of an external antenna, the number of built-in antennas is 1, the number of built-in antennas is M (described in FIG. 6B and FIG. 6C is 2 for simplicity), and the case of all built-in antennas (FIG. In FIG. 6B and FIG. 6C, the recovery process is performed in correspondence with 4).

Thus, according to the digital broadcast receiving apparatus in the present embodiment, it is possible to periodically evaluate the quality evaluation value (carrier C / N) of diversity reception during reception of broadcast radio waves. Therefore, the digital broadcast receiving apparatus according to the present embodiment can ensure reception quality while reducing power consumption even when the broadcast wave reception status of the digital broadcast receiving apparatus changes.

(Embodiment 5)
Next, a digital broadcast receiving apparatus according to Embodiment 5 of the present invention will be described with reference to FIGS. FIG. 9 is a flowchart showing a processing procedure of diversity reception control in Embodiment 5 of the present invention.

The digital broadcast receiving apparatus according to the present embodiment stores, for example, once-determined diversity reception control information in the RAM 207 as a storage unit together with the reception channel, and is stored in the RAM 207 when the same broadcast channel is received next time. Read and use control information. The digital broadcast receiving apparatus according to the present embodiment thus has a high control response.

Generally, the combination of antennas used for each desired broadcast channel is different. Assume that the combination of the reception channel and the control result of the antenna to be used is as shown in FIG. If the receiving antenna is determined for each of the 1 to 10 broadcast channels as shown in FIG. 10, the tuner unit to turn on the power is determined as a result. In the example of FIG. 10, the digital broadcast receiving apparatus uses all the built-in antennas 100 (1) to 100 (4) for 6-channel and 8-channel reception. In addition, the digital broadcast receiving apparatus is provided with two built-in antennas 100 (1) and 100 (2) or two built-in antennas 100 (3) and 100 (4) for receiving one channel, four channels, and nine channels. use. In the reception of 3 channels or 10 channels, the digital broadcast receiving apparatus uses the built-in antenna 100 (3) or the built-in antenna 100 (2). The digital broadcast receiving apparatus uses the external antenna 110 for reception of 2 channels or 5 channels.

If the relationship between the broadcast channel and the receiving antenna used for diversity reception is stored in the RAM 207 as a table, this storage table can be used as it is when the same channel is received next time. Then, it is often possible to set the optimum antenna used for diversity reception in a short time without executing the processing flows as shown in FIGS.

However, when an operation is performed on the main power supply of the digital broadcast receiving apparatus main body, it is highly possible that the position and orientation of the digital broadcast receiving apparatus have been changed. Therefore, it is appropriate not to use the data in the RAM 207 and to delete the stored data in the RAM 207 once. By using a volatile memory such as the RAM 207 for data storage, the stored data is surely erased when the main power is stopped, so that inappropriate control information is not used by mistake.

The flowchart shown in FIG. 9 shows a processing flow of diversity reception control using the control information stored in the RAM 207 as described above.

First, in step S701, the CPU 205 reads channel selection channel information by a user operation.

The CPU 205 reads the antenna switching information from the table stored in the RAM 207 shown in FIG. 10 so as to correspond to the read channel information.

If the antenna switching information is the external antenna 110 in step S702, the tuner unit 170 (N) connected to the external antenna 110 is turned on and the carrier switch unit 140 (N ). In step S707, a channel selection process is performed, broadcast reception is started, and the process ends.

If the built-in antenna is selected in the RAM information read in step S702, the antenna input switching unit 122 switches connection to the built-in antenna in step S711.

In step S712, the CPU 205 controls the power switch units 160 (1) to 160 (N) so that a desired tuner unit is powered on based on the RAM information.

In step S713, the CPU 205 controls the carrier switch units 140 (1) to 140 (N) so that a desired carrier is selected based on the RAM information.

In step S714, broadcast reception is started after the channel selection process, and the process ends.

For example, when channel 3 is selected, the CPU 205 controls the power switch 160 (3) to supply power only to the tuner unit 170 (3).

Next, the CPU 205 controls to turn on the carrier switch unit 140 (3) and performs demodulation using only this output carrier.

For example, when 4 channels are selected, the CPU 205 controls the power switch units 160 (3) and 160 (4) to supply power to the tuner units 170 (3) and 170 (4).

Next, the CPU 205 controls to turn on the carrier switch sections 140 (3) and 140 (4). Then, these two output carriers are combined by the carrier combining unit 201, and demodulation is performed by the combined carrier.

As described above, according to the digital broadcast receiving apparatus in the present embodiment, even when the reception channel is changed during reception of the broadcast radio wave, the past diversity control is used, so that the optimum diversity reception can be performed quickly and reliably. Can be set.

In addition, since the control information is stored in a volatile memory such as a RAM, inappropriate control information is used even when the user turns off the main power and moves the digital broadcast receiving apparatus to another location. There is nothing.

As described above, according to the digital broadcast receiving apparatus in the present embodiment, power is supplied to only the minimum necessary tuner unit while maintaining stable reception performance by diversity reception, so that power consumption is effectively reduced. It is possible to provide a digital broadcast receiving apparatus that is reduced in number.

In the above embodiment, the size of the carrier C / N is used as the quality evaluation parameter for the individual carrier and the combined carrier. However, if the carrier level is used, the detection circuit and the like can be further simplified. Further, a parameter such as a reception error rate acquired by the demodulation unit 202 may be used as the quality evaluation parameter. In this case, it is possible to evaluate the carrier quality with higher reliability.

In the above embodiment, two types of carrier C / N detection units, ie, an individual carrier C / N detection unit and a combined carrier C / N detection unit, are provided for carrier quality evaluation. It is also possible to control the unit to operate like an individual carrier C / N detection unit. That is, the individual carrier C / N may be detected by switching the carrier switch section of each tuner unit at a predetermined time and making a round, and performing detection in a time division manner every predetermined time.

In the above-described embodiment, it has been described that the power supply control of the tuner unit is performed as needed during the evaluation of the carrier C / N for diversity reception control in addition to the diversity reception. It is a short time. Therefore, as another form, during the evaluation of the carrier C / N, power is supplied to all the tuner units, and the power is controlled when control information for diversity reception can be acquired (the power of unnecessary tuner units is turned off). Off). Thereby, it is not necessary to frequently switch the power switch of the tuner unit, and the control can be simplified.

The present invention can be widely used not only for portable digital broadcast receivers with built-in antennas but also for portable terminal devices that receive digital broadcasts.

100 (1), 100 (2), 100 (N-1), 100 (N) Built-in antenna 110 External antenna 121 External antenna connection terminal 122 Antenna input switching unit 130 (1), 130 (2), 130 (N- 1), 130 (N) tuner sections 140 (1), 140 (2), 140 (N-1), 140 (N) carrier switch sections 150 (1), 150 (2), 150 (N-1), 150 (N) Individual carrier C / N detection unit 160 (1), 160 (2), 160 (N-1), 160 (N) Power switch unit 170 (1), 170 (2), 170 (N-1) ), 170 (N) Tuner unit 201 Carrier synthesis unit 202 Demodulation unit 203 Video / audio decoder unit 204 Composite carrier C / N detection unit 205 CPU (control unit)
206 System bus 207 RAM (storage unit)
208 Video signal 209 Audio signal 231 Error correction unit 232 TS decoder unit 233 AV decoder unit

Claims

N (N is a natural number of 2 or more) built-in antennas for receiving digital broadcast waves;
An external antenna for receiving digital broadcast waves;
An antenna input switching unit that switches between an input from any one of the N built-in antennas and an input from the external antenna;
N tuner units that are connected to the built-in antenna and the antenna input switching unit and output individual carrier signals having frequencies corresponding to predetermined broadcast channels;
N power switch units for supplying power to each of the N tuner units;
A carrier combining unit that outputs a combined carrier signal obtained by combining the individual carrier signals output from two or more tuner units among the N tuner units;
A demodulator that demodulates a video and audio signal from the individual carrier signal or the combined carrier signal;
A carrier quality evaluation value detector for detecting a quality evaluation value of the individual carrier signal or the combined carrier signal;
Based on at least one of the detection result of the carrier quality evaluation value detection unit and the antenna input switching information of the antenna input switching unit, a predetermined number of tuner units used for demodulation are selected, and the selection is made to the power switch unit A control unit for supplying power only to the predetermined number of the tuner units,
A digital broadcast receiving apparatus.
When the quality evaluation value of the individual carrier signal output from any of the N tuner units is equal to or higher than a predetermined reference value, the control unit is configured to use the individual carrier that provides the best quality evaluation value. The digital broadcast receiving apparatus according to claim 1, wherein the tuner unit that outputs a signal is selected as the tuner unit used for demodulation.
The control unit detects the quality evaluation value of the combined carrier signal from the M tuner units (M is a natural number of 2 or more and less than N) out of the N tuner units, and the M tuners When the quality evaluation value of the combined carrier signal of any one of the units is greater than or equal to a predetermined reference value, the quality evaluation value of the combined carrier signal is the combination of M tuner units. 2. The digital broadcast receiving apparatus according to claim 1, wherein M tuner units of the best combination are selected as tuner units used for demodulation.
The control unit, when the antenna input switching unit is switched to an input from the external antenna, selects the tuner unit connected to the antenna input switching unit as a tuner unit used for demodulation. Item 4. The digital broadcast receiver according to Item 1.
The antenna input switching unit further includes a signal detection function for detecting an input signal from the external antenna, and when detecting the input signal from the external antenna, switches to the input from the external antenna, The digital broadcast receiving apparatus according to claim 1, wherein the input from the built-in antenna is switched when the input signal from is not detected.
The control unit monitors the quality evaluation value periodically during broadcast reception, and when the quality evaluation value falls below a predetermined reference value, controls the N power switch units again. The digital broadcast receiver according to 1.
A storage unit for storing control information of the N power switch units for each broadcast channel;
2. The digital broadcast receiver according to claim 1, wherein the control unit controls the N power switch units using the control information of the broadcast channel read from the storage unit when a broadcast channel is selected.
The digital broadcast receiving apparatus according to claim 1, wherein the quality evaluation value is a C / N value of the individual carrier signal or the combined carrier signal.
A digital broadcast receiving method in a digital broadcast receiving apparatus comprising N (N is a natural number of 2 or more) built-in antennas for receiving digital broadcast waves and an external antenna for receiving digital broadcast waves,
Supplying power only to the tuner unit connected to the external antenna;
Detecting a quality evaluation value of an individual carrier signal of the tuner unit connected to the external antenna;
When the quality evaluation value of the individual carrier signal of the tuner unit connected to the detected external antenna is equal to or higher than a predetermined reference value, a tuning operation is performed at the tuner unit connected to the external antenna. And, if less than a predetermined reference value, supplying power to the tuner unit connected to the built-in antenna;
Detecting the quality evaluation value of the individual carrier signal of the tuner unit connected to the internal antenna;
When the quality evaluation value of the individual carrier signal of the tuner unit connected to the detected built-in antenna is equal to or higher than a predetermined reference value, only the tuner unit having the best quality evaluation value among the quality evaluation values And performing the channel selection operation and stopping the power supply to the tuner units other than the tuner unit, and if less than a predetermined reference value, performing the channel selection operation with a predetermined number of tuner units;
A digital broadcast receiving method.