Title:
IFFT CLOCK ADJUSTMENT DEVICE, DIGITAL TELEVISION BROADCAST DEVICE, AND METHOD OF ADJUSTING IFFT CLOCK
Document Type and Number:
Japanese Patent JP2014168164
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To successfully maintain an MER of a broadcast RF signal without being affected by temperature variation and the like of an oscillation output from a voltage-controlled oscillator that becomes a base of an IFFT clock.SOLUTION: An IFFT clock adjustment device 100 applies DAC data that is set, to a voltage-controlled oscillator 40 via a DAC 20, and thereby, supplies an oscillation output having a frequency depending on the analog signal to an OFDM modulator 71 as a clock signal. By using digital value generation means (a counter 50) generating a digital value that changes depending on an oscillation frequency (or an oscillation cycle) on the basis of the oscillation output outputted from the voltage-controlled oscillator 40, and an MER measurement unit 80, the DAC data is updated while measuring an MER of the broadcast RF signal. The digital value at the time when an almost-maximum value of the measurement value is obtained is recorded in a non-volatile memory 30 as a target digital value. Thereafter, the digital value based on the oscillation output of the voltage-controlled oscillator 40 and the target digital value are compared with each other successively, and the DAC data is updated until an error between both digital values is in a predetermined range.
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Inventors:
KURISU MOTOHIRO
MORITA SHINJI
MORITA SHINJI
Application Number:
JP2013039376A
Publication Date:
September 11, 2014
Filing Date:
February 28, 2013
Export Citation:
Assignee:
HIROTEKKU KK
International Classes:
H04J11/00; H03L1/02; H03L7/181; H04B1/04; H04H20/44
Domestic Patent References:
| JP2005079998A | 2005-03-24 | |||
| JP2011114469A | 2011-06-09 | |||
| JPH09162939A | 1997-06-20 |
Attorney, Agent or Firm:
Mutsuhiko Yamano