Patent ID: 9697391
Date: 2017-07-04
CPC Classifications: G06K,G07C,H03G

Claim:
1. A circuit, comprising: A first front end including a first controllable attenuator and a first amplifier, wherein the first controllable attenuator is for receiving a first wakeup pattern and in response generating a first attenuated RF wakeup pattern signal, and wherein the first amplifier is for amplifying the attenuated RF wakeup pattern signal to generate an amplified RF wakeup pattern signal; a first wakeup pattern detector comprising a first and a second stage, wherein the first stage is arranged to detect a first part of the wakeup pattern in the amplified RF wakeup pattern signal and, in response to the detection of the first part of the wakeup pattern, to generate a second stage wakeup signal, wherein the second stage is arranged to wakeup in response to the second stage wakeup signal, and wherein the first stage has a lower power consumption compared to the second stage; a control unit coupled to control the gain of the attenuator, wherein the control unit is configured to control the attenuator gain in response to a level of the amplified RF wakeup pattern signal; wherein the control unit includes a plurality of predetermined states for causing the first controllable attenuator to increase or to decrease the first attenuator gain in accordance with a predefined step size.