Wake-up circuit and an on board unit including the same, a filter, methods for frequency detection and filtering

摘要

A wake-up circuit, comprising: a control signal generation circuit comprising: a pulse generator configured to receive a digital signal and generate a pulse sequence signal with a frequency thereof; a first comparison circuit and a second comparison circuit both coupled to the pulse generator and configured to receive the pulse sequence signal; the first comparison circuit is configured to compare the frequency of the pulse sequence signal with a first threshold frequency and generate a first control signal; the second comparison circuit is configured to compare the frequency of the pulse sequence signal with a second threshold frequency and generate a second control signal; the frequency detector further comprises: an indication generation circuit configured to generate a wake-up indication if the frequency of the pulse sequence signal falls within a frequency range defined by the first and second threshold frequencies.