- 专利标题: Demodulating frequency shift keying modulated input signal
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申请号: US14867014申请日: 2015-09-28
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公开(公告)号: US09660849B2公开(公告)日: 2017-05-23
- 发明人: Zhiling Sui , Zhijun Chen , Zhihong Cheng , Jiangtao Pan
- 申请人: Freescale Semiconductor, Inc.
- 申请人地址: US TX Austin
- 专利权人: FREESCALE SEMICONDUCTOR, INC.
- 当前专利权人: FREESCALE SEMICONDUCTOR, INC.
- 当前专利权人地址: US TX Austin
- 代理商 Charles E. Bergere
- 优先权: CN201510232649 20150327
- 主分类号: H04B7/02
- IPC分类号: H04B7/02 ; H03F3/45 ; H04L27/156 ; H04W56/00 ; H04L7/00 ; H04L27/16
摘要:
A method of demodulating an FSK modulated input signal whose frequency varies between first and second frequencies. The input signal is delayed by a plurality of cycles, providing a second signal. A succession of phase reference signals having respective incrementally greater phase delays relative to the input signal are provided. Samples of the phase reference signals are taken at intervals determined by the second signal. A transition between the first and second frequencies is detected when the relative values of the samples of the phase reference signals remain constant during a plurality of intervals after varying. A high speed clock is not required to perform the demodulation.