JP2007295253A - Reception control device and switching control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize a reception state by performing gain control in a tuner prior to an antenna switching selection operation to shorten a time required for stabilizing a variation in the level of an IF signal input. <P>SOLUTION: A reception control device includes: a switching and selection part 2 for switching and selection among a plurality of antennas 1; a switched beam control part 3 which controls switching and selection among the plurality of antennas 1 and outputs an antenna switching start notification signal prior to switching and selection; a tuner 6 which selects a channel from a signal received by a switched and selected antenna 1 and amplifies a broadcast signal of the channel; an automatic gain control part 7 which outputs a gain control signal for controlling the amount of gain control in the tuner 6 on the basis of the broadcast signal amplified by the tuner 6; and an offset control part 5 which adds an offset value to the gain control signal from the automatic gain control part 7 to generate a gain control signal with an offset in accordance with the antenna switching start notification signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reception control device that receives and reproduces a broadcast from a broadcasting station, and a switching control method in the device, for example, a reception control device and a switching control method that are suitable for use in a vehicle-mounted television receiver or the like. .

In an environment where the receiver moves at a high speed, such as a vehicle-mounted television receiver, a phenomenon called Doppler shift in which the frequency of the broadcast radio wave from the broadcast station may occur may occur.
Due to this phenomenon, for example, phase noise occurs in the vicinity of the output frequency, and in particular, a receiver (or receiving device) using an orthogonal frequency division multiplexing (OFDM) system introduced in terrestrial digital broadcasting or the like. Is a problem.

For this reason, in order to reduce the influence of phase noise due to the Doppler shift, switched beam control is known that suppresses phase noise by switching and selecting a plurality of antennas and automatically controlling the antenna directivity. ing.
Here, the switched beam control will be described with reference to FIG. 5 showing the configuration of a conventional receiving apparatus.

FIG. 5 is a block diagram showing a main part of a conventional receiving apparatus. This receiving apparatus 200 includes a plurality of antennas 12 (four in FIG. 5), an antenna selector 13, and a switched beam control unit. 14, a tuner 15, an automatic gain control unit (AGC) 16, and a demodulation circuit 17.
The antenna 12 is used for receiving broadcast radio waves from a broadcasting station, and the antenna selector 13 is for performing a switching operation for switching and selecting an antenna to be used by the tuner 15 from the plurality of antennas 12. It is.

The tuner 15 is for receiving a broadcast radio wave and selecting a channel. The tuner 15 includes an amplifier (not shown) for amplifying a received signal to a certain level. The gain control amount of the amplifier is It is controlled by a PWM (Pulse Width Modulation) signal from the AGC 16.
The AGC 16 generates and outputs a PWM signal for controlling the gain control amount of the amplifier based on the signal output from the tuner 15, and the demodulation circuit 17 demodulates the output signal from the tuner 15. Is for.

The switched beam control unit 14 is for performing switched beam control for controlling the directivity of the antenna 12 by controlling the switching selection operation of the plurality of antennas 12 by the antenna selector 13.
That is, the switched beam control described above is to optimize the receiving state by switching and selecting antennas 12 having different directivity characteristics to optimize the antenna directivity, and the phase noise due to the Doppler shift described above. Is to suppress the influence of

  On the other hand, in the receiving apparatus, the AGC 16 performs gain control of an amplifier (not shown) using a PWM signal in order to keep the level of an input signal [intermediate frequency (IF) signal] from the tuner 15 constant. However, it may not be able to follow sudden and large level fluctuations of the input signal (input electric field). When the level fluctuation cannot be followed, the receiving apparatus cannot perform an accurate reception process, and the reception state may deteriorate.

For this reason, in order to solve such a problem, a reception control method for the reception apparatus that always maintains a stable reception state is considered.
For example, in Patent Document 1 below, each reception level of a plurality of antennas is compared, a compensation signal for automatic gain control is generated based on a difference in relative reception levels obtained thereby, and then selected. A method of performing automatic gain control so as to correspond to the reception level of the antenna is disclosed.

Further, Patent Document 2 discloses the characteristics of incoming wave transmission paths based on correlation detection information and FFT window position detection information of incoming waves received by a plurality of receiving systems, signal level fluctuations and frequency deviation amounts of the incoming waves. And AGC control information is generated using the estimation result, and AGC of a plurality of receiving systems is efficiently performed.
Furthermore, Patent Document 3 predicts a received signal level from the distance between the current position information and a communication partner station at the start of communication, and performs gain control using a predicted gain for obtaining a desired received signal level in a variable gain amplifier as an initial value. Controlling the amount is disclosed.

  Further, Patent Document 4 includes a variable gain amplifying unit that can adjust a signal amplification factor and a plurality of gain control units that generate a gain control signal based on the output of the variable gain amplifying unit in an automatic gain control device. It is disclosed that automatic gain control can be tracked even when a change occurs in a desired radio frequency band by selecting one gain control signal and outputting it to variable gain control means.

Further, in Patent Document 5, the state in which the received signal of the tuner circuit or the variable gain amplifier circuit changes abruptly is determined by the determination circuit, and the channel selection switching is performed by switching the AGC time constant of the AGC circuit based on the determination output. It has been disclosed that AGC can follow a transient phenomenon such as time or when an antenna input electric field suddenly changes.
Japanese Patent No. 3533686 JP 2001-345778 A JP 2003-209477 A JP-A-8-84088 JP 2001-148819 A

  As described above, in the receiving apparatus 200 described above, gain control is performed so that the level fluctuation of the input electric field of the IF signal input from the tuner 15 to the AGC 16 is suppressed. When twelve switching controls are performed, level fluctuations frequently occur, and it is necessary to perform gain control that further suppresses the level fluctuations compared to the conventional case.

Here, the level variation of the IF signal when, for example, the number of antennas 12 used is reduced by the switched beam control will be described with reference to FIG.
FIG. 6 shows (a) a switched beam antenna switching waveform, (b) a gain control amount in the AGC 16 and (c) a level of the IF input signal before and after the number of antennas 12 used is reduced by the switched beam control. FIG. 6 is a diagram illustrating timing. In FIG. 6, with the dotted line as a boundary, the left side represents before the decrease in the number of antennas 12 used, and the right side represents after the decrease.

  The switched beam antenna switching waveform of (a) represents the time change of the control signal waveform output from the switched beam control unit 14 to the antenna selector 13. For example, when this control signal is ON, the antenna 12 is switched. The antenna selector 13 is selected so that four antennas are used, and the antenna selector 13 is controlled so as to perform switching selection so that two antennas 12 are used when OFF. Here, a state in which the control signal is switched from ON to OFF (the antenna 12 is reduced from four to two) is shown.

The gain control amount in (b) represents the time change of the gain control amount in the amplifier in the tuner 15, and the IF input signal level in (c) is the time of the level of the IF signal output from the tuner 15. It represents a change.
In the example shown in FIG. 6, when the antenna switching is selected by the switched beam control (the switched beam antenna switching waveform (a) transitions from ON to OFF), the IF input signal level (c) changes abruptly (here Then, based on this change, the gain control amount is changed (in this case, temporarily increased) so as to keep the IF signal level constant by the PWM signal from the AGC 16. Thereafter, both (b) and (c) fluctuate with each other, and the IF input signal level (c) eventually settles to a constant value.

  However, since the method described in each of the above-described patent documents requires a certain amount of time to stabilize the input level, for example, when switching of antennas frequently occurs due to switched beam control, There is a possibility that the gain control cannot be normally performed because a further level fluctuation occurs before the gain (gain) in the tuner 15 is controlled. In such a case, if the input level is low or high for a long time, a reception error may occur and the reception state of the broadcast radio wave may deteriorate.

  The present invention was devised in view of such a problem, and the IF signal input level is achieved by performing gain control in the tuner 15 prior to the antenna switching selection operation by the switched beam control. The purpose is to further reduce the time required to stabilize the fluctuation and stabilize the reception state.

In order to achieve the above object, the present invention is characterized by using the following reception control device and switching control method. That is,
(1) A reception control apparatus according to the present invention controls a switching selection unit that switches and selects a plurality of antennas, and controls switching selection of the plurality of antennas by the switching selection unit, and prior to performing switching selection of the antennas, An antenna switching control unit that outputs a switching start notification signal; a tuner that selects and amplifies signals received from an antenna that is switched and selected by the switching selection unit; and the tuner that is based on a broadcast signal amplified by the tuner. An automatic gain control unit that outputs a gain control signal for controlling a gain control amount in the signal, and an offset gain control signal by adding an offset value to the gain control signal from the automatic gain control unit according to the antenna switching start notification signal And an offset control unit for generating.

(2) Here, the offset control unit may include an offset value control unit that can change the offset value, and the offset value control unit may control the gain control amount by changing the offset value. Good.
(3) The offset control unit may further include an offset timing control unit that can change a timing for changing the offset value.

  (4) Also, the switching control method of the present invention selects and amplifies a plurality of antennas, a switching selection unit that switches and selects a plurality of antennas, and a signal received by the antenna that is switched and selected by the switching selection unit. A switching control method in a receiver comprising a tuner and an automatic gain control unit that outputs a gain control signal for controlling a gain control amount in the tuner based on the signal amplified by the tuner, An antenna switching start notification step for outputting an antenna switching start notification signal prior to switching selection of the antenna by the switching selection unit, and when the antenna switching start notification signal is output, a gain control signal from the automatic gain control unit An offset gain control signal generation step for generating an offset gain control signal by adding an offset value to the offset value; The offsetting gain control signal generated in Preparative with a gain control signal producing step is characterized in that includes an offset with a gain control signal input step of inputting to the tuner.

According to the present invention, at least one of the following effects or advantages can be obtained.
(1) The antenna switching start notification signal is output to the offset control unit before the antenna switching selection by the switched beam control is performed, and the gain control signal is controlled in advance before the input level of the IF signal fluctuates. Therefore, it is possible to minimize the time required for the level fluctuation that occurs at the time of antenna switching. Therefore, it is possible to stabilize the reception state and improve the performance of the entire receiving apparatus.

(2) The gain control amount of the tuner is controlled by an offset gain control signal obtained by adding an offset value to the gain control signal, and the tuner gain control amount can be controlled only by changing the offset value. A device can be realized by using a simple addition / subtraction circuit.
(3) Furthermore, since the offset timing control unit provided in the offset control unit can also set the timing for changing the offset value, finer gain control is possible and the input level fluctuation of the IF signal can be efficiently controlled. Can be suppressed.

  (4) Since the input signal (IF signal) from the tuner can be kept at a more constant level, the reception state is stabilized, thereby making it possible to reduce the discomfort of the user (user).

Hereinafter, a reception control device and a switching control method (hereinafter simply referred to as “reception device”) of the present invention will be described with reference to the drawings. The receiving device can be applied to, for example, a vehicle-mounted device such as a vehicle-mounted television receiver, and can be applied to a receiving device mounted on a mobile phone or a PDA (Personal Digital Assistance) terminal in the future. It is.
(1) Description of Embodiment FIG. 1 is a block diagram showing a configuration of a main part of a receiving apparatus 100 according to an embodiment of the present invention.

As shown in FIG. 1, the receiving apparatus 100 according to the present embodiment includes, for example, a plurality of antennas 1, an antenna selector 2, a switched beam control unit 3, an antenna switching monitoring unit 4, a PWM (Pulse Width Modulation). ) An offset control unit 5, a tuner 6, an AGC (Automatic Gain Control) 7, and a demodulation circuit 8 are provided.
Here, the plurality of antennas 1 are used for receiving broadcast radio waves from a broadcasting station, and an antenna selector (switching selection unit) 2 switches and selects an antenna to be used from among the plurality of antennas 1. This is for performing a switch operation, and is realized by, for example, a hardware switch.

  A switched beam control unit (antenna switching control unit) 3 performs switched beam control (antenna switching control) for controlling the directivity of the antennas by controlling switching selection of the plurality of antennas 1 by the antenna selector 2. Further, an antenna switching start notification signal (antenna switching start timer signal) relating to time information until antenna switching selection is performed is output to the antenna switching monitoring unit 4 prior to the antenna switching selection control. It is. In addition, information regarding the increase / decrease of the antenna 1 during the switched beam control (switched beam antenna switching waveform information) can be output to the antenna switching monitoring unit 4.

  Based on the antenna switching start notification signal, the antenna switching monitoring unit 4 generates an antenna switching notification signal that triggers generation of a PWM signal with offset (gain control signal with offset) in the PWM offset control unit (offset control unit) 5. Prior to the antenna switching selection control, it is output to the PWM offset control unit 5. Note that the switched beam control unit 3 may be configured to directly output the antenna switching start notification signal to the PWM offset control unit 5, and in this case, the receiving apparatus can monitor the antenna switching from the configuration of FIG. 1. The configuration is such that part 4 is deleted. Furthermore, the antenna switching start notification signal may include switched beam antenna switching waveform information.

  The PWM offset control unit (offset control unit) 5 generates a PWM signal with an offset (automatic gain signal with offset) obtained by adding an offset value to the PWM signal (gain control signal) from the AGC 7 based on the antenna switching start notification signal. This is output to the tuner 6, and the timing for adding the offset value and the setting for the offset amount can be set by the user from the outside. These setting methods and their effects will be described later with reference to FIGS.

The tuner 6 is for receiving a broadcast radio wave and selecting a channel, and is provided with a plurality (two in this embodiment), each having an amplifier (not shown) for amplifying the received signal. Is done.
An AGC (automatic gain control unit) 7 generates and outputs a PWM signal (gain control signal) for performing gain control of the tuner 6 based on the broadcast signal output level (IF signal output level) amplified by the tuner 6. The plurality of tuners 6 are provided respectively. Note that what is generated and output for the AGC 7 to perform gain control in the tuner 6 is not limited to the PWM signal, but may be any signal (gain control signal) capable of gain control.

The demodulation circuit 8 is for demodulating the output signal from the tuner 6 and outputting it as a transport stream (TS), and is shared by the plurality of tuners 6.
With such a configuration, the gain control of the received signal in the tuner 6 can be performed prior to the antenna switching control by the switched beam control unit 3, and the time required for gain control can be shortened compared to the conventional case. Become. For this reason, even when the antenna switching control is frequently performed, the gain control can be performed normally. Therefore, the receiving apparatus can perform accurate and stable reception control.

Hereinafter, the operation of the receiving apparatus according to the present embodiment configured as described above will be described in detail with reference to FIG.
FIG. 2 is a block diagram showing an example of the configuration of the PWM offset control unit 5.
As shown in FIG. 2, the PWM offset control unit 5 includes, for example, an offset timing control unit 9, a set value register 10, and an offset value addition / subtraction control unit 11.

  Here, the offset timing control unit 9 uses the antenna switching start notification signal as an opportunity to set the offset value based on the value of the offset timing (for example, offset timing 1, 2, 3) held in the set value register 10. The timing for addition / subtraction is generated and output as an offset timing signal. As a result, the offset value can be changed stepwise according to time and added to the PWM signal, so that fine gain control can be performed, and fluctuations in the input level of the IF signal can be further suppressed.

  The set value register 10 operates as an offset value control unit capable of changing the offset value by cooperating with the offset timing control unit 9 and the offset value addition / subtraction control unit 11, and holds various settings related to the offset value. belongs to. In this example, the offset timing and the offset value are held. These setting values can be changed by register access from the outside. For example, the increment and decrement of the offset value can be set individually, so that finer gains can be obtained. Control becomes possible, and further suppression of fluctuations in the input level of the IF signal can be achieved. . In this example, offset timings 1, 2, and 3 are held as offset timings, and offset values A, B, C, and D are held as offset values.

  The offset value addition / subtraction control unit 11 is for adding or subtracting an offset value to / from the PWM signal from the AGC 7, and an offset timing signal from the offset timing control unit 9, an offset value from the set value register 10, This is for adding an offset to the PWM signal from the AGC 7. Note that these offset timing and offset value settings can be selectively changed from a plurality of settings held in the set value register 10, so that the optimum offset for suppressing the fluctuation level of the IF signal The attached PWM signal can be generated in a short time. Moreover, the generation of the PWM signal with an offset can be realized by using a simple addition / subtraction circuit, and space saving and cost saving can also be achieved. Furthermore, at this time, it is also possible to receive the increase / decrease information of the antenna identified from the switched beam antenna switching waveform (switched beam antenna switching waveform information) from the antenna switching monitoring unit 4, thereby using the antenna. Since the setting of the offset timing and the offset amount can be switched according to the increase / decrease in the number, the gain control operation can be further speeded up.

The offset value addition / subtraction control unit 11 outputs an offset PWM control signal to the tuner 6, and gain control in the tuner 6 is performed based on the offset PWM control signal.
The PWM offset control unit 5 described above is similarly provided for each of the plurality of tuners 6, and settings relating to offset (here, offset timing and offset value) are individually set for the plurality of tuners 6. Can be set. As a result, even when various antenna switching selections are made, it is possible to individually set an offset and perform gain control, so that more effective gain control can be performed, and IF signal level fluctuations Can be further suppressed.

  The set value register 10 described above may be realized by a storage device such as a dedicated memory or HDD, or may be realized by a storage device that also shares some or all of other functions. As a result, the setting value related to the timing can be stored in the storage device, so that the circuit scale necessary for the timing processing can be reduced. The functions of the switched beam control unit 3, the antenna switching monitoring unit 4, the PWM offset control unit 5, the tuner 6, the AGC 7, and the demodulation circuit 8 are, for example, those of a CPU or MPU mounted on the receiving device 100. This is realized by a processor (not shown) reading and operating a predetermined application program. The program may be provided (installed) in the storage device in a form stored in a recording medium such as a flexible disk, a CD-ROM, a DVD-ROM / RAM, a magnetic disk, a magneto-optical disk, or the like. You may provide with the form downloaded via a network (communication line).

(1.1) Description of Operation Hereinafter, the switching control method in the reception control apparatus of the present embodiment configured as described above will be described with reference to the flowchart shown in FIG.
As shown in FIG. 3, in this switching control method, first, prior to the antenna switching selection operation by the antenna selector 2, the switched beam control unit 3 outputs an antenna switching notification signal to the antenna switching monitoring unit 4, Further, the antenna switching monitoring unit 4 outputs an antenna switching notice signal to the PWM offset control unit 5 (step S10, antenna switching start notification step).

  Then, the PWM offset control unit 5 determines whether the number of antennas has increased based on the switched beam antenna switching waveform information from the switched beam control unit 3 included in the antenna switching notice signal (step S1). When it is determined that the number of antennas has increased (yes route in step S1), the offset timing and the offset value when the number of antennas has increased are set in the set value register 10 (steps S2 and S3). On the other hand, if it is not determined that the number of antennas has increased (no route of step S1), the offset timing and the offset value when the number of antennas has decreased are set in the set value register 10 (step S4, step S4). S5). The offset timing and offset value for the case where the number of antennas increases or decreases here means that the gain at the tuner 6 is optimal when the number of antennas increases or decreases, that is, the level variation of the IF signal. This is an offset setting capable of generating a PWM signal with an offset, which enables gain control such that is effectively suppressed. Further, the same offset setting may be used when the number of antennas is increased and when the number is decreased, and in this case, the processing of steps S1, S4, and S5 is not required, and switching beam antenna switching is performed. Since waveform information is not required, the processing can be speeded up.

Next, the offset timing control unit 9 reads the offset timing held in the set value register 10 (step S6), and generates and outputs an offset timing signal.
Then, the offset value addition / subtraction control unit 11 reads the offset timing signal, reads the offset value held in the set value register 10 (step S7), and further reads the PWM signal from the AGC 7 (step S8). In step S9, a PWM signal with offset is generated (step S20, gain control signal generation step with offset). That is, the offset PWM signal is generated when the antenna switching start notification signal is in the ON state.

Next, the switching control method is realized by inputting the gain control signal with offset generated in step S9 to the tuner 6 (step S30, gain control signal input step with offset).
Here, the effect obtained by the above processing will be specifically described with reference to FIGS. 4 (a) and 4 (b).

  FIG. 4A shows a switched beam antenna switching waveform, an antenna switching notice signal (antenna switching start notification signal), an offset, a gain control amount with an offset, and an IF before and after the number of antennas 1 is decreased by switched beam control. FIG. 4B is a timing chart for explaining the offset value and the offset timing setting in detail. The dotted line (i) in the figure represents the timing when the antenna switching start notification signal is generated and input to the PWM offset control unit 5, and the dotted line (ii) indicates that the switched beam antenna switching waveform is ON. To OFF, that is, the timing when the antenna switching selection is performed and the number of antennas is decreased, and the dotted line (iii) indicates the timing when the antenna switching start notification signal is turned OFF.

  First, in the sections (i) to (ii), the antenna switching start notification signal is turned on by the antenna switching monitoring unit 4 at the timing shown in (i). Here, since the antenna switching control is performed by the switched beam control unit 3 at the timing shown in (ii), the antenna switching start notification signal is in the ON state prior to the antenna switching selection. Become. Note that how much the antenna switching start notification signal precedes the antenna switching selection can be appropriately changed by the user, for example, by changing a predetermined value set in the switched beam control unit 3.

  For example, when the antenna switching start notification signal is turned on at an earlier timing than the timing (i) when the antenna switching start notification signal shown in FIG. 4 is turned on, the change in the IF input signal level is further moderated. You can also. However, if the timing (i) is set too early, the gain control process may not be in time for the antenna switching selection process when the antenna switching selection is frequently performed. It is preferable that the most appropriate timing is set according to the situation such as the occurrence frequency of the antenna switching selection process.

In response to the antenna switching start notification signal being turned on, the PWM offset control unit 5 generates an offset by the above-described steps, and the offset-added PWM signal is output to the tuner 6. As a result, the amount of gain control with offset increases, and the IF input signal level gradually increases.
On the other hand, in the sections (ii) to (iii), first, the antenna selector 2 performs switching selection processing of the antenna 1 at the timing shown in (ii). As a result, the IF input signal level starts to decrease, but gain control is performed based on the PWM signal with an offset prior to the antenna switching selection process. Yes.

In this section, since the offset also starts to decrease, the gain control amount with offset starts to converge.
Then, at the timing shown in (iii), the antenna switching start notification signal is turned OFF and the offset is also zero. At this time, the gain control amount with offset and the IF input signal level have already converged.

Here, offset value and offset timing setting will be described with reference to FIG.
Dotted lines (i), (iii), (iv), and (v) represent timings at which the offset values change, and offset values A to D and offset timings (1) to (3) are set values, respectively. The set value is stored in the register 10 in advance.

  In this example, by setting the offset value as A = B = −C = −D> 0 and setting the offset timing as (1) = (2) = (3), the gain control amount with offset is The gain is controlled so that it does not change abruptly, that is, the IF input signal level does not fluctuate rapidly and greatly, but these set values can be freely changed. For example, when the number of antennas increases, it is possible to effectively control the IF input signal level by setting the offset value to −A = −B = C = D> 0, and the offset timing. By increasing the number of set values and changing the offset value to a small value, the gain control amount can be controlled more finely, and the level fluctuation of the IF input signal can be further suppressed. The offset value may be changed linearly (continuously).

With the above processing, the IF input signal signal from the tuner 6 can be maintained at a constant level in a shorter time, so that the reception state is stabilized, thereby making it possible to reduce user discomfort.
(2) Others Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and may be arbitrarily modified and implemented without departing from the spirit of the present invention. be able to.

  For example, the above receiving apparatus does not necessarily have all the various functions described above. For example, when operating as a reception control apparatus, the antenna 1 may not be equipped, and when there is only one tuner 6, the PWM offset control unit 5 and the AGC 7 may be one each. Further, if the set value register 10 is composed of a large-capacity register, more set values related to offset (offset value, offset timing, etc.) can be obtained. Further, the antenna 1 may be three or less or five or more, and may be provided with three or more offset control units 5, tuners 6 and automatic gain control units 7, respectively.

(3) Appendix (Appendix 1)
A switching selection unit for switching and selecting a plurality of antennas;
An antenna switching control unit that controls switching selection of the plurality of antennas by the switching selection unit and outputs an antenna switching start notification signal prior to performing switching selection of the antenna;
A tuner for selecting and amplifying from a signal received by an antenna switched and selected by the switching selection unit;
An automatic gain control unit that outputs a gain control signal for controlling a gain control amount in the tuner based on the broadcast signal amplified by the tuner;
A reception control device comprising: an offset control unit that generates an offset gain control signal by adding an offset value to the automatic gain signal from the automatic gain control unit according to the antenna switching start notification signal .

(Appendix 2)
The offset control unit
The reception control apparatus according to appendix 1, wherein an offset value control unit capable of changing the offset value is provided, and the offset value control unit controls the gain control amount by changing the offset value.

(Appendix 3)
The offset value control unit
The reception control apparatus according to appendix 2, wherein the offset value is changed stepwise.
(Appendix 4)
The offset value control unit
4. The reception control device according to appendix 2 or appendix 3, wherein the offset value increment and decrement are individually set.

(Appendix 5)
An offset control unit provided for each of the plurality of tuners,
5. The reception control apparatus according to any one of appendices 1 to 4, wherein each setting relating to the offset value is individually provided.
(Appendix 6)
The offset control unit
The reception control apparatus according to any one of appendices 1 to 5, further comprising an offset timing control unit capable of changing a timing for changing the offset value.

(Appendix 7)
The offset timing control unit
The reception control apparatus according to appendix 6, wherein a plurality of offset timing values for determining the timing for changing the offset value are provided, and the offset timing value is selectively changed.

(Appendix 8)
An offset control unit provided for each of the plurality of tuners,
8. The reception control device according to appendix 6 or appendix 7, wherein each setting relating to the offset timing value is individually provided.
(Appendix 9)
The offset control unit
9. The reception control device according to any one of appendices 6 to 8, wherein the setting relating to the offset value and the offset timing value is provided corresponding to the increase or decrease of the antenna.

(Appendix 10)
A plurality of antennas, a switching selection unit that switches and selects the plurality of antennas, a tuner that selects and amplifies a signal received by the antenna that is switched and selected by the switching selection unit, and the signal amplified by the tuner Based on the above, a switching control method in a receiving device including an automatic gain control unit that outputs an automatic gain signal for controlling a gain control amount in the tuner,
An antenna switching start notification step for outputting an antenna switching start notification signal prior to performing the antenna switching selection by the switching selection unit;
When the antenna switching start notification signal is output, an offset gain control signal creation step for generating an offset gain control signal by adding an offset value to the automatic gain signal from the automatic gain control unit;
A switching control method comprising: an offset-added gain control signal input step for inputting the offset-added gain control signal generated in the offset-added gain control signal generating step to the tuner.

(Appendix 11)
In the gain control signal creation step with offset,
The switching control method according to appendix 10, wherein the gain control amount is controlled by changing the offset value.
(Appendix 12)
In the gain control signal creation step with offset,
The switching control method according to appendix 11, wherein the offset value is changed stepwise.

(Appendix 13)
In the gain control signal creation step with offset,
The switching control method according to appendix 11 or appendix 12, characterized in that the increment and decrement of the offset value can be set individually.
(Appendix 14)
In the gain control signal creation step with offset,
The switching according to any one of appendices 10 to 13, wherein the setting relating to the offset value can be individually created for each PWM offset control unit provided for each of the plurality of tuners. Control method.

(Appendix 15)
In the gain control signal creation step with offset,
15. The switching control method according to any one of appendices 10 to 14, wherein the timing for changing the offset value can be changed.
(Appendix 16)
In the gain control signal creation step with offset,
16. The switching control method according to appendix 15, wherein a plurality of offset timing values for determining the timing for changing the offset value are created, and the offset timing value can be selectively changed.

(Appendix 17)
In the gain control signal creation step with offset,
The switching control method according to appendix 15 or appendix 16, wherein the setting relating to the offset timing value can be individually created for each of the plurality of tuners.
(Appendix 18)
In the gain control signal creation step with offset,
18. The switching control method according to any one of appendices 15 to 17, wherein the setting relating to the offset value and the offset timing value can be created corresponding to the increase or decrease of the antenna.

(Appendix 19)
Multiple antennas to receive broadcast waves,
A switching selection unit for switching and selecting the plurality of antennas;
An antenna switching control unit that controls switching selection of the plurality of antennas by the switching selection unit and outputs an antenna switching start notification signal prior to performing switching selection of the antenna;
A tuner for selecting and amplifying from a signal received by an antenna switched and selected by the switching selection unit;
An automatic gain control unit for outputting an automatic gain signal for controlling a gain control amount in the tuner based on the broadcast signal amplified by the tuner;
An offset control unit for generating an offset gain control signal by adding an offset value to the automatic gain signal from the automatic gain control unit in accordance with the antenna switching start notification signal from the antenna switching monitoring unit. A receiving device.

It is a block diagram which shows the structure of the principal part of the receiver which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the principal part of the PWM offset control part which concerns on one Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the receiver which concerns on one Embodiment of this invention. (A), (b) is a timing chart for demonstrating the various signal waveforms which flow through the receiver which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the conventional receiver. It is a timing chart for demonstrating the various signal waveforms which flow through the conventional receiver.

Explanation of symbols

1 Antenna 2 Antenna selector (switching selection section)
3 Switched beam control unit (antenna switching control unit)
4 Antenna switching monitoring unit 5 PWM offset control unit (offset control unit)
6 Tuner 7 AGC (Automatic Gain Control Unit)
8 Demodulation circuit 9 Offset timing control unit 10 Set value register 11 Offset value addition / subtraction control unit 100 Receiver

Claims (4)

A switching selection unit for switching and selecting a plurality of antennas;
An antenna switching control unit that controls switching selection of the plurality of antennas by the switching selection unit and outputs an antenna switching start notification signal prior to performing switching selection of the antenna;
A tuner for selecting and amplifying from a signal received by an antenna switched and selected by the switching selection unit;
An automatic gain control unit that outputs a gain control signal for controlling a gain control amount in the tuner based on the broadcast signal amplified by the tuner;
A reception control device comprising: an offset control unit that generates an offset gain control signal by adding an offset value to the automatic gain signal from the automatic gain control unit according to the antenna switching start notification signal . The offset control unit
The reception control device according to claim 1, further comprising an offset value control unit capable of changing the offset value, wherein the offset value control unit controls the gain control amount by changing the offset value. . The offset control unit
The reception control apparatus according to claim 1, further comprising an offset timing control unit capable of changing a timing of changing the offset value. A plurality of antennas, a switching selection unit that switches and selects the plurality of antennas, a tuner that selects and amplifies a signal received by the antenna that is switched and selected by the switching selection unit, and the signal amplified by the tuner Based on the above, a switching control method in a receiving device including an automatic gain control unit that outputs an automatic gain signal for controlling a gain control amount in the tuner,
An antenna switching start notification step for outputting an antenna switching start notification signal prior to performing the antenna switching selection by the switching selection unit;
When the antenna switching start notification signal is output, an offset gain control signal creation step for generating an offset gain control signal by adding an offset value to the automatic gain signal from the automatic gain control unit;
A switching control method comprising: an offset-added gain control signal input step for inputting the offset-added gain control signal generated in the offset-added automatic gain signal generating step to the tuner.

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