| 摘要 |
A phase locked loop including an in-phase detector (IPD), a quadrature phase detector (QPD), a frequency detector (FD), a squelch, a filter, and a voltage controlled oscillator (VCO). The in-phase detector has an IPD sample input, an IPD input, and an IPD output, where the IPD sample input is coupled to a data input. The quadrature phase detector has a QPD sample input, a QPD input, and a QPD output, where the QPD sample input is coupled to the data input. The frequency detector has a first FD input coupled to the IPD output, a second FD input coupled to the QPD output, and a FD output. The squelch has a squelch input, an enable input, and a squelch output where the squelch input is coupled to the IPD output and the squelch enable is coupled to the FD output. The filter has a filter input coupled to the squelch output and a filter output. The voltage controlled oscillator has a VCO input coupled to the filter output, a VCO in-phase output, and a VCO quadrature output. The VCO in-phase output is coupled to the IPD input and the VCO quadrature output is coupled to the QPD input. The PLL has an improved pull-in range with reduced chance of out-of-phase lock.
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