发明名称 |
Signal demodulation method and apparatus therefor using multi-ary sampling |
摘要 |
A signal demodulation apparatus using a multi-ary sampling for beam formation of a received signal reduces a difference between a sampling point of time of an in-phase signal and a sampling point of time of a quadrature signal due to an existing secondary sampling method. Each of a plurality of analog-to-digital converters produces a first in-phase signal and at least two first quadrature signals adjacent to the first in-phase by sampling each input signal input via a plurality of channels at a sampling point of time having a sampling period of the input signal and other sampling points of time having a sampling interval smaller than the sampling period of the input signal. A quadrature component calculator of each channel produces second quadrature signals in which an error due to a difference between the sampling point of time of the first in-phase signal and the sampling points of time of the first quadrature signal is reduced. A first accumulator accumulates first in-phase signals of all the channels to produce a second in-phase signal and a second accumulator accumulates second quadrature signals of all the channels to produce a third quadrature signal. The second in-phase signal and the third quadrature signal are used for detection of an envelope signal of the received signal. The apparatus can be used in a sonar and a radar as well as an ultrasonic image apparatus, rendering an effect capable of obtaining an in-phase signal and a quadrature signal from which an error due to a difference between sampling points of time is remarkably reduced compared with the existing secondary sampling method.
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申请公布号 |
US5774499(A) |
申请公布日期 |
1998.06.30 |
申请号 |
US19950418569 |
申请日期 |
1995.04.07 |
申请人 |
MEDISON CO., LTD. |
发明人 |
AHN, YOUNG BOK;CHO, WEON-HEE |
分类号 |
H03D3/06;H03D3/00;(IPC1-7):H04L5/12;A61B8/00 |
主分类号 |
H03D3/06 |
代理机构 |
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代理人 |
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