JP2009124263A - Equalizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To turn an equalization function automatically at the time of starting, to stabilize operation of an apparatus even immediately after the equalization function is turned on, and to deliver a signal without delay. <P>SOLUTION: An inputted IF signal is distributed to a bypass mode and an equalization mode at a distribution section 31. Consequently, a signal is always inputted to an equalization section 37. The equalization section 37 equalizes an inputted signal and delivers a monitor signal indicating whether equalization is effective or ineffective to a control section 39. An equalizer 30 selects a bypass mode at the time of starting an apparatus, and switches the mode to an equalization mode by performing switching control of switching sections 32 and 38 upon receiving a monitor signal indicating that equalization is effective. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an equalization apparatus that suppresses multipath and multipath fading in a relay apparatus using, for example, an OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme.

  In the terrestrial digital broadcasting system, for the purpose of expanding the broadcasting service area and resolving difficult viewing areas, a large number of relay devices are distributed in a predetermined area, and broadcast wave signals based on the OFDM modulation system are relayed in multiple stages at each relay device. The method is adopted. This relay device relays a broadcast wave signal from a base station. However, when a broadcast wave signal is relayed, it may not be accurately relayed due to the effects of multipath, multipath fading, and the like. Therefore, an equalizing device capable of equalizing broadcast wave signals is installed in the relay device in order to suppress multipath, multipath fading, and the like.

  The equalization apparatus suppresses multipath, multipath fading, and the like that hinder signal relay by performing equalization processing of a broadcast wave signal. The conventional equalization apparatus starts operation according to the state when the power is turned off immediately after the apparatus is activated. Therefore, when the equalization function is off when the power is turned off, it is expected that the operation of the apparatus will be stabilized, and the equalization process of the broadcast wave signal is started when the user turns on the equalization function manually or remotely. .

  However, in the method of manually turning on the equalization function, there is a problem that the operation of the equalization apparatus is not always stable even when the equalization function is turned on, in addition to being troublesome. Furthermore, since the broadcast wave signal is equalized after the equalization function is turned on, there is a delay from the time when the equalization function is turned on until the first broadcast wave signal subjected to the equalization process is output. Could occur.

A control method has been proposed in which the level of a broadcast wave signal during equalization processing is monitored, and the equalization function is turned off when the signal component to be suppressed is smaller than the main signal component (for example, patents). Reference 1).
Japanese Patent Laid-Open No. 2001-333342

  As described above, in the conventional equalizer, it is necessary to manually turn on the equalization function when the equalization function is off when the equalization apparatus is started. Even so, the operation of the equalizer was not always stable. Further, since the equalization process is started after the equalization function is turned on, there is a possibility that a delay may occur until the output.

  The present invention has been made under the circumstances described above, and the purpose of the present invention is to automatically turn on the equalization function at the time of startup, and the operation of the apparatus is stabilized even immediately after the equalization function is turned on. Another object of the present invention is to provide an equalization apparatus capable of transmitting a signal without delay.

  In order to achieve the above object, an equalization apparatus according to the present invention equalizes a first distribution unit that distributes a broadcast wave signal in an intermediate frequency band to two systems, and one of the distributed broadcast wave signals. An equalization means for notifying that the equalization process is valid when the equalization process is valid, and notifying that the equalization process is invalid when the equalization process is not valid; The first switching unit that receives the other distributed broadcast wave signal and the broadcast wave signal from the equalization means and selectively derives one of them, and when the activation is instructed, When the first switching unit selects the distributed broadcast wave signal and then receives a notification that the equalization processing is valid, the first switching unit receives the broadcast wave signal from the equalization means. And a control unit for selecting.

  The equalization apparatus having the above configuration distributes the broadcast wave signal to the path via the equalization means and the path not via the equalization means by the first distribution unit. At the time of starting the equalization apparatus, the first switching unit derives a broadcast wave signal of a route that does not pass through the equalization means. Thereafter, when a notification that the equalization processing is effective is transmitted from the equalization means to the control section, the first switching section derives a broadcast wave signal from the equalization means by switching control of the control section. I try to switch.

  According to the present invention, the equalization function can be automatically turned on after the apparatus is started, and the operation is stable immediately after the equalization function is turned on, and signals can be sent without delay. An equalization device can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a relay device according to an embodiment of the present invention. In FIG. 1, an OFDM modulation type broadcast wave signal transmitted from a base station is received by a receiving antenna 10, frequency-converted to an intermediate frequency band IF (Intermediate Frequency) signal by a frequency converter 20, and then equalized. Derived to device 30. The broadcast wave signal is subjected to suppression of multipath, multipath fading, and the like by the equalization device 30, frequency-converted to a radio frequency band by the frequency conversion unit 40, and output from the transmission antenna 50.

  FIG. 2 is a block diagram showing the configuration of the equalization apparatus 30 according to an embodiment of the present invention. In FIG. 2, the IF signal is distributed into two systems by the distribution unit 31, one being supplied to the analog-digital (A / D) conversion unit 33 and the other being supplied to the switching unit 32.

  The IF signal is converted into a digital signal by the analog-digital conversion unit 33, is orthogonally demodulated by the orthogonal demodulation unit 34, becomes a baseband OFDM modulated wave, and the adjacent channel is suppressed by the band limiting filter 35. The OFDM modulated wave in which the adjacent channel is suppressed is distributed into two systems by the distribution unit 36, one of which is supplied to the equalization unit 37 and the other is supplied to the switching unit 38.

  The equalization unit 37 performs multipath equalization and symbol determination processing on the input OFDM modulated wave. At this time, the equalization unit 37 demodulates the OFDM modulated wave and performs equalization processing by obtaining frame synchronization of the information signal on the time axis obtained after demodulation. Here, when the frame synchronization of the information signal is established and equalization processing of the input OFDM modulated wave can be performed effectively, the equalization unit 37 sends a monitoring signal indicating that the equalization function is effective to the control unit 39. Notify When the frame synchronization cannot be achieved and the equalization process cannot be effectively performed, a monitoring signal indicating that the equalization function is invalid is notified to the control unit 39.

  The switching unit 38 receives the OFDM modulated wave distributed by the distributing unit 36 and the equalized OFDM modulated wave, and selectively derives one of them. The derived OFDM modulated wave is orthogonally modulated by the orthogonal modulation unit 310 and converted into an analog signal in the IF band by the digital-analog (D / A) conversion unit 311.

  The switching unit 32 receives the analog signal in the IF band and the IF signal distributed by the distributing unit 31 and selectively derives one of the signals. The derived signal is output to the frequency conversion unit 40.

  The abnormality detection unit 312 detects an abnormality in each component of the equalization apparatus 30 and outputs an alarm signal to the control unit 39. Examples of the abnormality herein include occurrence of an abnormality in the clock signal at the time of signal conversion in the digital-analog conversion unit 311, for example.

  The control unit 39 receives a monitoring signal from the equalization unit 37, an alarm signal from the abnormality detection unit 312 and an equalization function on / off signal from an external device (not shown), and based on each signal, The switching units 32 and 38 are controlled to be switched. Here, the switching unit 32 outputs the IF signal from the distribution unit 31 in the bypass mode, and the switching unit 32 outputs the analog signal from the digital-analog conversion unit 311 while the switching unit 38 outputs from the distribution unit 36. A mode for deriving an OFDM modulated wave is a direct mode, and a mode in which the switching unit 38 derives an OFDM modulated wave from the equalization unit 37 in a state where the switching unit 32 derives an analog signal from the digital-analog conversion unit 311. This is referred to as a conversion mode.

  FIG. 3 is a diagram illustrating mode switching by the control unit 39 according to an embodiment of the present invention. When the equalization apparatus 30 is activated, the equalization function in the equalization unit 37 is invalid, and the switching units 32 and 38 are controlled to enter the bypass mode. In the bypass mode at the time of startup, even when an equalization function on / off signal from an external device and an alarm signal from the abnormality detection unit 312 are received, the mode is not switched.

  After starting the apparatus, the control unit 39 monitors the monitoring signal from the equalization unit 37, and receives the monitoring signal indicating that the equalization function is valid, controls the switching units 32 and 38 to change the mode to the equalization mode. Switch to. When the mode is the equalization mode, when the equalization function off signal is received, the mode is switched to the direct mode, and when the equalization function on signal is received, the mode is switched to the equalization mode.

  When the state of the input IF signal changes after the apparatus is activated, the equalization processing in the equalization unit 37 may not work effectively. At this time, the equalization unit 37 transmits a monitoring signal indicating that the equalization function is invalid to the control unit 39. When the control unit 39 receives a notification that the equalization function is invalid, the control unit 39 switches the mode from the equalization mode to the direct mode. Here, even if the equalization function ON / OFF signal is received, the mode remains in the direct mode.

  Also, when an alarm signal is received in the equalization mode or direct mode after the apparatus is activated, the mode is switched to the bypass mode regardless of whether the equalization processing is enabled / disabled and the equalization function on / off signal.

  As described above, the equalization apparatus according to the above embodiment is in the bypass mode when the equalization apparatus is activated, and after the activation, the equalization unit 37 issues a monitoring signal indicating that the equalization processing is effective. When the mode is activated, the mode is automatically switched to the equalization mode. As a result, the equalization function by the equalization unit 37 can be automatically turned on, and the operation of the equalization apparatus is stable even immediately after the equalization function is turned on. Further, since the broadcast wave signal is distributed to the bypass mode and the equalization mode by the distribution unit 31, the OFDM modulation wave is always input to the equalization unit 37. For this reason, the equalization processing can be performed even during the bypass mode, and even after the equalization function is turned on, a signal delay due to the equalization processing does not occur.

  Therefore, the equalization apparatus 30 can automatically turn on the equalization function after the apparatus is activated, and the operation is stable immediately after the equalization function is turned on, and the signal can be sent without delay. .

  When the state of the input IF signal changes and the equalization processing becomes invalid, the mode is switched to the direct mode. Thereby, even when equalization processing cannot be performed effectively, it is possible to suppress adjacent channels of the OFDM modulated wave.

  Further, the equalization mode and the direct mode can be switched by an equalization function on / off signal from an external device. As a result, the equalization function can be switched on / off by an instruction from the outside.

  Further, the mode can be switched to the bypass mode by an alarm signal from the abnormality detection unit 312. Accordingly, when an abnormality occurs in each component of the apparatus, a broadcast wave signal that may be affected by the component that caused the abnormality is not output.

  The present invention is not limited to the above embodiment. For example, although the equalization apparatus provided in the relay apparatus has been described, the present invention is not limited to the relay apparatus, and can be similarly implemented even when provided in the reception apparatus, for example.

  Moreover, although the case where a clock synchronization cannot be taken is mentioned as an example where an equalization process becomes invalid, the factor which an equalization process becomes invalid is not necessarily limited to this.

  Furthermore, the present invention can be embodied by modifying the constituent elements without departing from the spirit of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

The block diagram which shows the structure of a relay apparatus provided with the equalization apparatus which concerns on one Embodiment of this invention. The block diagram which shows the function structure of the equalization apparatus which concerns on the said embodiment. The figure which shows the mode switching in the control part which concerns on the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Reception antenna, 20 ... Frequency conversion part, 30 ... Equalization apparatus, 31 ... Distribution part, 32 ..., Switching part, 33 ... A / D conversion part, 34 ... Orthogonal demodulation part, 35 ... Band-limiting filter, 36 ... Distributing unit, 37 ... equalizing unit, 38 ... switching unit, 39 ... control unit, 310 ... quadrature modulation unit, 311 ... D / A converting unit, 312 ... abnormality detecting unit, 40 ... frequency converting unit, 50 ... transmitting antenna.

Claims (7)

A first distribution unit that distributes broadcast wave signals in the intermediate frequency band to two systems;
Equalize one of the distributed broadcast wave signals, notify that the equalization process is valid if the equalization process is valid, and equalize if the equalization process is not valid An equalization means for notifying that the processing is invalid;
A first switching unit that receives the other distributed broadcast wave signal and the broadcast wave signal from the equalization means, and selectively derives one of them;
When the activation is instructed, the first switching unit causes the first switching unit to select the distributed broadcast wave signal, and then receives the notification that the equalization processing is valid. And a control unit for selecting a broadcast wave signal from the equalization means. The equalizing means includes
An analog-to-digital converter that digitally converts one of the distributed broadcast wave signals;
An orthogonal demodulator for orthogonally demodulating the digitally converted broadcast wave signal;
A band limiting unit for limiting a frequency band including a noise component of the orthogonally demodulated broadcast wave signal;
Equalizes broadcast wave signal with a limited frequency band, and notifies that the equalization process is effective if the equalization process is effective, and if the equalization process is not effective, etc. An equalization unit for notifying that the equalization processing is invalid;
An orthogonal modulation unit that orthogonally modulates a broadcast wave signal from the equalization unit;
The equalization apparatus according to claim 1, further comprising: a digital-analog conversion unit that performs analog conversion on the orthogonally modulated broadcast wave signal. The equalizing means includes
A second distribution unit that distributes the broadcast wave signal with the frequency band limited to two systems, and outputs one to the equalization unit;
A second switching unit that receives the other broadcast wave signal distributed by the second distribution unit and the broadcast wave signal from the equalization unit, and selectively derives one of them;
When the control unit receives a notification that the equalization process is valid, the control unit causes the second switching unit to select a broadcast wave signal from the equalization unit, and the equalization process is invalid. 3. The equalization apparatus according to claim 2, wherein when receiving the notification, the second switching unit is caused to select the other broadcast wave signal distributed by the second distribution unit. 4. The equalization according to claim 3, wherein the control unit performs switching control of the second switching unit in a state where the first switching unit selects a broadcast wave signal from the equalization means. apparatus. An abnormality detection means for detecting an abnormality in each component and transmitting an alarm signal,
The equalization apparatus according to claim 1, wherein the control unit causes the first switching unit to select the other broadcast wave signal distributed when receiving the alarm signal. A reception unit for receiving an equalization function on signal and an equalization function off signal input from the outside;
When the equalization function ON signal is received when the equalization processing in the equalization means is valid, the control unit selects the broadcast wave signal from the equalization unit as the second switching unit. 4. The equalization according to claim 3, wherein when the equalization function off signal is received, the second switching unit is caused to select the other broadcast wave signal distributed by the second distribution unit. apparatus. The equalization according to claim 6, wherein the control unit performs switching control of the second switching unit in a state where the first switching unit selects a broadcast wave signal from the equalization means. apparatus.

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