JP2009171278A - Receiving device and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver including a plurality of amplifiers connected in series, the receiver suppressing the occurrence of error in a demodulation processor 24 when a pre-stage amplifier 19 is brought from OFF state to ON state. <P>SOLUTION: A control section 26 in the receiver 16 of the present invention is configured to control an amplification factor of a second amplifier 20 to be lower than or equal to a predetermined value when bringing a first amplifier 19 from OFF state to ON state. Thus, when the control section 26 controls the pre-stage first amplifier 19 from OFF state to ON state, even when a strength of an output signal from the first amplifier 19 becomes high rapidly, since the amplification factor of the post-stage second amplifier 20 is controlled to be lower than or equal to the predetermined value, a rapid increase in an output signal from the second amplifier 20 can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives a signal and an electronic apparatus using the receiving apparatus.

  Hereinafter, a conventional receiving apparatus will be described with reference to FIG. FIG. 5 is a block diagram of an electronic apparatus equipped with a conventional receiving apparatus. In FIG. 5, a conventional electronic device 1 includes an antenna 2 that receives a digital TV broadcast, a receiving device 3 connected to the output side of the antenna 2, and a decoding processing unit connected to the output side of the receiving device 3. 4 and a display unit 5 connected to the output side of the decoding processing unit 4. The receiving device 3 is connected to the antenna 2 on the basis of the oscillation signal output from the local oscillating unit 8 and is capable of switching between an ON state and an OFF state, and an output of the first amplifying unit 6. A second amplifying unit 7 that is connected to the side and whose amplification degree changes, a mixing unit 9 that converts the frequency of the signal output from the second amplifying unit 7 based on the output of the local oscillating unit 8, An AD conversion unit 10 connected to the output side for converting an analog signal into a digital signal, and a demodulation processing unit 11 connected to the output side of the AD conversion unit 10 are provided. Further, the receiving device 3 is connected between the AD conversion unit 10 and the demodulation processing unit 11 to detect the signal level output from the AD conversion unit 10 and the detection result of the level detection unit 12 And a control unit 13 that changes the degree of amplification of the second amplifying unit 7 and controls switching between the ON state and the OFF state of the first amplifying unit 6.

  Hereinafter, the operation of the control unit 13 in the conventional receiving apparatus 3 will be described. As an initial state, the first amplifying unit 6 is assumed to be in an OFF state, that is, a non-functional state.

  The control unit 13 decreases the degree of amplification of the second amplification unit 7 as the intensity of the output signal of the second amplification unit 7 increases, and decreases as the intensity of the output signal of the second amplification unit 7 decreases. The amplification degree of the second amplification unit 7 is increased. However, when the amplification degree of the second amplifying unit 7 increases to a certain value A, even if the intensity of the output signal of the second amplifying unit 7 decreases, it does not increase but becomes substantially constant. Therefore, in order to increase the intensity of the output signal of the second amplification unit 7 before the amplification level of the second amplification unit 7 becomes substantially constant, the control unit 13 sets the amplification level of the second amplification unit 7 to the threshold value B ( If ≦ A) or more, the first amplifier 6 is controlled from the OFF state to the ON state. Thereby, the intensity of the output signal from the first amplifying unit 6 increases, and accordingly, the output signal intensity from the second amplifying unit 7 also increases. As a result, the intensity of the output signal of the second amplifying unit 7 can be kept appropriate.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent No. 3454882

  However, when the control unit 13 controls the first amplifying unit 6 from the OFF state to the ON state, the output signal from the second amplifying unit 7 is suddenly increased by the intensity of the output signal from the first amplifying unit 6. The strength also increases rapidly. As a result, there is a problem that an input signal larger than the input intensity limit of the AD conversion unit 10 is input to the AD conversion unit 10 and an error occurs in the demodulation processing unit 11.

  FIG. 6 shows the output signal intensity from the second amplifying unit 7 over time. The vertical axis represents the output signal intensity from the second amplifying unit 7, and the horizontal axis represents time t. The input intensity limit P of the AD conversion unit 10 is indicated by a broken line. According to FIG. 6, when t = T1 when the control unit 13 controls the first amplifying unit 6 from the OFF state to the ON state, the output signal intensity from the second amplifying unit 7 increases rapidly at t = T1. It can be seen that the input intensity limit P is exceeded.

  Therefore, the present invention has an object to suppress the occurrence of errors in a demodulation processing unit when a previous amplification unit is turned from an OFF state to an ON state in a receiving device including a plurality of amplification units connected in series. To do.

  In order to achieve the above object, the control unit in the receiving apparatus of the present invention controls the amplification of the second amplification unit to be equal to or less than a predetermined value when the first amplification unit is switched from the OFF state to the ON state. It is.

  With the above configuration, when the control unit controls the first amplification unit in the previous stage from the OFF state to the ON state, even if the intensity of the output signal from the first amplification unit suddenly increases, Since the amplification degree is controlled to be equal to or less than the predetermined value, it is possible to suppress the output signal from the second amplification unit from rapidly increasing. As a result, it is possible to suppress an input signal larger than the input intensity limit of the AD conversion unit from being input to the AD conversion unit, and it is possible to suppress the occurrence of an error in the demodulation processing unit.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an electronic device in which the receiving device according to Embodiment 1 is mounted. Hereinafter, an electronic device in which the receiving device in Embodiment 1 is mounted will be described with reference to FIG. In FIG. 1, an electronic device 14 includes an antenna 15 that receives a digital TV broadcast, a receiving device 16 connected to the output side of the antenna 15, and a decoding processing unit 17 connected to the output side of the receiving device 16. And a display unit 18 connected to the output side of the decoding processing unit 17. The receiving device 16 further includes a first amplifying unit 19 connected to the antenna 15 and capable of switching between an ON state and an OFF state. The switching between the ON state and the OFF state of the first amplifying unit 19 may be switching between the ON state and the OFF state of the signal amplifying function of the first amplifying unit 19, and the power supply of the first amplifying unit 19 is turned on. It may be switched between the state and the OFF state, or may be switched between the ON state and the OFF state of both the signal amplification function of the first amplifying unit 19 and the power source. The signal amplification function OFF state of the first amplifying unit 19 is realized by short-circuiting the first amplifying unit 19, for example. Further, the receiving device 16 is connected to the output side of the first amplifying unit 19, and the signal output from the second amplifying unit 20 based on the output of the second amplifying unit 20 whose amplification degree changes and the local oscillating unit 21. A frequency conversion unit 22, an AD conversion unit 23 connected to the output side of the mixing unit 22 for converting an analog signal into a digital signal, and a demodulation processing unit 24 connected to the output side of the AD conversion unit 23. Is provided. Further, the receiving device 16 is connected between the AD conversion unit 23 and the demodulation processing unit 24 to detect the signal level output from the AD conversion unit 23, and the detection result of the level detection unit 25. And a control unit 26 that changes the amplification degree of the second amplifying unit 20 and switches and controls the ON state and the OFF state of the first amplifying unit 19. The mixing unit 22 may be connected to the previous stage of the first amplifying unit 19, or may be connected between the first amplifying unit 19 and the second amplifying unit 20. Further, the level detection unit 25 may be connected to the previous stage of the AD conversion unit 23 or may be connected to the previous stage of the mixing unit 22. In this case, the level detection unit 25 detects the analog output value of the second amplification unit 20. Further, a filter may or may not be connected between each component of the electronic device 14. Note that the second amplifying unit 20 may change the amplification degree continuously or may change the amplification degree discretely. The second amplifying unit 20 may be connected to the input side of the first amplifying unit 19.

  Hereinafter, the operation of the control unit 26 in the receiving device 16 of the present invention will be described. As an initial state, it is assumed that the first amplifying unit 19 is in an OFF state, that is, a non-functioning state.

  The control unit 26 decreases the amplification degree of the second amplification unit 20 as the intensity of the output signal of the second amplification unit 20 increases, and decreases as the intensity of the output signal of the second amplification unit 20 decreases. The amplification degree of the second amplification unit 20 is increased. Thereby, the intensity of the output signal of the second amplifying unit 20 is kept substantially constant. That is, even if the signal reception level of the antenna 15 fluctuates, the control unit 26 keeps the intensity of the output signal of the second amplifying unit 20 almost constant by the above control. However, when the amplification degree of the second amplifying unit 20 increases to a certain value A, even if the intensity of the output signal of the second amplifying unit 20 decreases, it does not increase but becomes substantially constant. Therefore, in order to increase the intensity of the output signal of the second amplification unit 20 before the amplification level of the second amplification unit 20 becomes substantially constant, the control unit 26 sets the amplification level of the second amplification unit 20 to the threshold value B ( If ≦ A) or more, the first amplifier 19 is controlled from the OFF state to the ON state. Thereby, the intensity of the output signal from the first amplifying unit 19 increases, and accordingly, the intensity of the output signal from the second amplifying unit 20 also increases. As a result, the intensity of the output signal of the second amplifying unit 20 can be kept appropriate.

  Further, the control unit 26 performs control so that the amplification degree of the second amplification unit 20 becomes a predetermined value or less immediately before or simultaneously with the first amplification unit 19 from the OFF state to the ON state. This predetermined value is usually the amplification degree of the difference between the amplification degree of the second amplification part 20 and the amplification degree of the first amplification part 19 immediately before the first amplification part 19 is switched from the OFF state to the ON state. Note that the time indicated by “immediately before” is a time during which a digital signal is time-interleaved at the longest, and is preferably a time equal to or less than a half of one symbol period. Thus, when the control unit 26 controls the first amplification unit 19 in the previous stage from the OFF state to the ON state, even if the intensity of the output signal from the first amplification unit 19 suddenly increases, the second amplification in the latter stage Since the amplification degree of the unit 20 is controlled to be equal to or less than a predetermined value, it is possible to suppress the output signal intensity from the second amplification unit 20 from rapidly increasing. As a result, it is possible to suppress an input signal that is larger than the input intensity limit of the AD conversion unit 23 from being input to the AD conversion unit 23, and to suppress occurrence of an error in the demodulation processing unit 24.

  FIG. 2 shows the output signal intensity from the second amplifying unit 20 over time. The vertical axis represents the output signal intensity from the second amplifying unit 20, and the horizontal axis represents time t. The input intensity limit P of the AD conversion unit 23 is indicated by a broken line. If t = T1 when the control unit 26 controls the first amplification unit 19 from the OFF state to the ON state, the control unit 26 determines that the amplification degree of the second amplification unit 20 is equal to or less than a predetermined value immediately before t = T1. It is controlled to become. As shown in FIG. 2, when the control unit 26 controls the first amplification unit 19 in the previous stage from the OFF state to the ON state, it is possible to suppress the output signal intensity from the second amplification unit 20 from rapidly increasing. I understand that.

  Note that when the first amplifying unit 19 is switched from the OFF state to the ON state, the control unit 26 controls the second amplifying unit 20 so that the amplification level of the second amplifying unit 20 is equal to or lower than the amplification level of the second amplifying unit 20 immediately before that. May be. Even in this configuration, it is possible to suppress the output signal intensity from the second amplifying unit 20 from rapidly increasing.

  Further, the control unit 26 may cancel this control after controlling the amplification degree of the second amplification unit 20 to be a predetermined value or less. Thereby, since the second amplifying unit 20 can again change the amplification degree according to the reception environment, the intensity of the output signal of the second amplifying unit 20 can be kept appropriate again.

  Then, the case where the control part 26 controls the 1st amplification part 19 from ON state to an OFF state is demonstrated below.

  The intensity of the output signal from the first amplifying unit 19 suddenly decreases, so that the output signal intensity from the second amplifying unit 20 also decreases rapidly, and the intensity of the output signal from the second amplifying unit 20 becomes an appropriate value. It takes a long time to become. As a result, there is a problem that the state in which the input signal intensity to the AD conversion unit 23 becomes smaller than the conversion resolution of the AD conversion unit 23 continues for a long period of time, and an error occurs in the demodulation processing unit 24 for a long period of time.

  FIG. 3 shows the output signal intensity from the second amplifying unit 20 over time. The vertical axis represents the output signal intensity from the second amplifying unit 20, and the horizontal axis represents time t. According to FIG. 3, when t = T2 when the control unit 26 controls the first amplifying unit 19 from the OFF state to the ON state, the output signal intensity from the second amplifying unit 7 also decreases rapidly at t = T2. Thus, it can be seen that it takes a long time for the intensity of the output signal of the second amplifying unit 20 to reach an appropriate value.

  Therefore, when the amplification degree of the second amplification unit 20 becomes equal to or less than the threshold value, the control unit 27 immediately or simultaneously controls the first amplification unit 19 from the ON state to the OFF state. Control so that it is equal to or greater than a predetermined value. This predetermined value is usually an amplification factor obtained by adding the amplification factor of the second amplification unit 20 and the amplification factor of the first amplification unit 19 immediately before the first amplification unit 19 is switched from the ON state to the OFF state. Thus, when the control unit 26 controls the first amplifying unit 19 from the ON state to the OFF state, even if the output signal from the first amplifying unit 19 suddenly decreases, the second amplifying unit in the subsequent stage Since the amplification degree of 20 is controlled to be equal to or higher than a predetermined value, it is possible to prevent the state where the output signal intensity from the second amplification unit 20 is low from continuing for a long period of time. As a result, the input intensity of the AD conversion unit 23 is maintained at an appropriate value, and long-term errors in the demodulation processing unit 24 can be suppressed.

  FIG. 4 shows the output signal intensity from the second amplifying unit 20 over time. The vertical axis represents the output signal intensity from the second amplifying unit 20, and the horizontal axis represents time t. Assuming that t = T2 when the control unit 26 controls the first amplification unit 19 from the ON state to the OFF state, immediately after t = T2, the control unit 26 increases the amplification degree of the second amplification unit 20 to a predetermined value or more. It is controlled to become. According to FIG. 4, when the control unit 26 controls the first amplification unit 19 in the previous stage from the ON state to the OFF state, the state where the output signal intensity from the second amplification unit 20 is small is prevented from continuing for a long time. You can see that

  In addition, the control part 26 is controlled so that the amplification degree of the 2nd amplification part 20 becomes more than the amplification degree of the 2nd amplification part 20 immediately before that, when making the 1st amplification part 19 into an OFF state from ON state. May be. Even in this configuration, it is possible to suppress a state in which the output signal intensity from the second amplifying unit 20 is low for a long time.

  Further, the control unit 26 may cancel this control after controlling the amplification degree of the second amplification unit 20 to be equal to or higher than a predetermined value. Thereby, since the second amplifying unit 20 can again change the amplification degree according to the reception environment, the intensity of the output signal of the second amplifying unit 20 can be kept appropriate again.

  The first amplifying unit 19 may be configured such that the received signal is input and the amplification degree is discretely changed. Furthermore, the discrete width of the amplification change of the first amplification unit 19 may be larger than the discrete width of the amplification change of the second amplification unit 20. The control unit 26 changes the amplification level of the second amplification unit 20 based on the signal level output from the second amplification unit 20, and the first amplification unit 20 when the amplification level of the second amplification unit 20 is equal to or greater than a threshold value. The amplification unit 19 may be configured to control the amplification level from a low level to a high level. That is, when changing the first amplification unit 19 from a state where the amplification degree is small to a state where the amplification degree is large, the control unit 26 controls the amplification degree of the second amplification unit 20 to be a predetermined value or less.

  As a result, when the control unit 26 controls the first amplification unit 19 in the previous stage from a state in which the amplification degree is small to a state in which the amplification degree is large, even if the intensity of the output signal from the first amplification unit 19 suddenly increases Since the amplification degree of the second amplification unit 20 at the subsequent stage is controlled to be equal to or less than a predetermined value, it is possible to suppress the output signal intensity from the second amplification unit 20 from rapidly increasing. As a result, it is possible to suppress an input signal that is larger than the input intensity limit of the AD conversion unit 23 from being input to the AD conversion unit 23, and to suppress occurrence of an error in the demodulation processing unit 24.

  In the above configuration, the control unit 26 controls the first amplification unit 19 from a state in which the amplification degree is large to a state in which the amplification degree is small when the amplification degree of the second amplification unit 20 is equal to or less than the threshold value. When the first amplification unit 19 is changed from a state in which the amplification degree is large to a state in which the amplification degree is small, the configuration may be such that the amplification degree of the second amplification unit 20 is controlled to be a predetermined value or less.

  As a result, when the control unit 26 controls the first amplification unit 19 from a state in which the amplification degree is large to a state in which the amplification degree is small, even if the output signal from the first amplification unit 19 suddenly decreases, Since the amplification degree of the second amplifying unit 20 is controlled to be equal to or higher than a predetermined value, it is possible to suppress the state where the output signal intensity from the second amplifying unit 20 is low for a long time. As a result, the input intensity of the AD conversion unit 23 is maintained at an appropriate value, and long-term errors in the demodulation processing unit 24 can be suppressed.

  The receiving device of the present invention, in a receiving device including a plurality of amplifying units connected in series, suppresses the occurrence of errors in the demodulation processing unit when the preceding amplifying unit is switched from the OFF state to the ON state. This is particularly useful for electronic devices such as stationary TVs, mobile terminals with TV functions, and in-vehicle receivers.

1 is a block diagram of an electronic device equipped with a receiving device according to Embodiment 1 of the present invention. The figure which showed the output signal strength from the 2nd amplifier of the receiver in Embodiment 1 of this invention with time The figure which showed the output signal strength from the 2nd amplifier of the receiver in Embodiment 1 of this invention with time The figure which showed the output signal strength from the 2nd amplifier of the receiver in Embodiment 1 of this invention with time Block diagram of an electronic device equipped with a conventional receiver The figure which showed the output signal strength from the 2nd amplification part of the conventional receiver over time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 14 Electronic device 15 Antenna 16 Receiver 17 Decoding processing part 18 Display part 19 1st amplification part 20 2nd amplification part 21 Local oscillation part 22 Mixing part 23 AD conversion part 24 Demodulation processing part 25 Level detection part 26 Control part

Claims (13)

A first amplifying unit capable of switching between an ON state and an OFF state when a reception signal is input;
A second amplifying unit connected to the output side or the input side of the first amplifying unit to change the amplification degree;
The amplification factor of the second amplification unit is changed based on a signal output from a circuit in the second stage of the second amplification unit or the first amplification unit, and the amplification factor of the second amplification unit becomes equal to or greater than a threshold value. A control unit that controls the first amplification unit from an OFF state to an ON state when
The control unit is a receiving device that controls the amplification degree of the second amplification unit to be equal to or less than a predetermined value when the first amplification unit is changed from an OFF state to an ON state. 2. The receiving device according to claim 1, wherein the control unit controls the amplification degree of the second amplifying unit to be equal to or less than a predetermined value at the same time or immediately before the first amplifying unit is switched from the OFF state to the ON state. The predetermined value is an amplification degree of a difference between an amplification degree of the second amplification part and an amplification degree of the first amplification part immediately before the first amplification part is changed from an OFF state to an ON state. The receiving device described. The receiving apparatus according to claim 1, wherein the predetermined value is an amplification degree of the second amplifying unit immediately before the first amplifying unit changes from an OFF state to an ON state. The receiving apparatus according to claim 1, wherein the control unit releases the control after controlling the amplification degree of the second amplifying unit to be a predetermined value or less. A first amplifying unit capable of switching between an ON state and an OFF state when a reception signal is input;
A second amplifying unit connected to the output side or the input side of the first amplifying unit to change the amplification degree;
The amplification level of the second amplification unit is changed based on a signal output from a subsequent circuit of the second amplification unit or the first amplification unit, and the amplification level of the second amplification unit is equal to or less than a threshold value. A control unit that controls the first amplification unit from an ON state to an OFF state when
The control unit is a receiving device that controls the amplification degree of the second amplification unit to be equal to or higher than a predetermined value when the first amplification unit is changed from an ON state to an OFF state. The receiving apparatus according to claim 6, wherein the control unit controls the amplification degree of the second amplification unit to be equal to or higher than a predetermined value at the same time or immediately after the first amplification unit is changed from the ON state to the OFF state. The predetermined value is an amplification factor obtained by adding the amplification factor of the second amplification unit and the amplification factor of the first amplification unit immediately before the first amplification unit is changed from the ON state to the OFF state. The receiving device described. The receiving apparatus according to claim 6, wherein the predetermined value is an amplification degree of the second amplifying unit immediately before the first amplifying unit changes from an ON state to an OFF state. The receiving device according to claim 6, wherein the control unit releases the control after controlling the amplification degree of the second amplifying unit to be a predetermined value or more. A first amplifying unit that receives the received signal and discretely changes the amplification degree;
A second amplifying unit connected to the output side or the input side of the first amplifying unit to change the amplification degree;
The amplification factor of the second amplification unit is changed based on a signal output from a circuit in the second stage of the second amplification unit or the first amplification unit, and the amplification factor of the second amplification unit becomes equal to or greater than a threshold value. A control unit that controls the first amplification unit from a low amplification level to a high amplification level when
The control unit is a receiving device that controls the amplification of the second amplification unit to be equal to or less than a predetermined value when the first amplification unit is changed from a low amplification level to a high amplification level. A first amplifying unit capable of switching between a state in which a received signal is input and the amplification degree is large and the amplification degree is small;
A second amplifying unit connected to the output side or the input side of the first amplifying unit to change the amplification degree;
The amplification level of the second amplification unit is changed based on a signal output from a subsequent circuit of the second amplification unit or the first amplification unit, and the amplification level of the second amplification unit is equal to or less than a threshold value. A control unit that controls the first amplification unit from a state in which the amplification degree is large to a state in which the amplification degree is small in the case of
The control unit is a receiving device that controls the amplification of the second amplification unit to be equal to or higher than a predetermined value when the first amplification unit is changed from a high amplification state to a low amplification state. A receiving device according to any one of claims 1 to 12,
An electronic device comprising a display unit connected to the output side of the receiving device.

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