Patent ID: 7283840

Claim:
A transceiver operable to process Bluetooth compatible signals and wireless local area network compatible (WLAN-compatible) signals, the transceiver comprising: a radio-frequency unit; a digital baseband unit configured to generate a mode control signal indicative of a Bluetooth-compatible mode or a WLAN-compatible mode; a dual-mode filter and amplifier unit having a first Bluetooth-compatible mode and in said second mode, the dual-mode filter and amplifier unit coupled to the radio frequency unit and digital baseband unit and configured to select an operating mode from the first Bluetooth-compatible mode and second WLAN-compatible mode responsive to said mode control signal; the dual-mode filter and amplifier unit comprising a dual-mode amplifier further comprising: at least a first stage having an operational amplifier that is in use during both the first Bluetooth-compatible mode and the second WLAN-compatible mode; at least a first feedback component including at least one resistor; at least a first switch coupled to said feedback component and said operational amplifier having a first mode and a second mode, such that in said first mode the dual-mode filter and amplifier is operable in said first Bluetooth-compatible mode and the feedback component is disconnected from said operational amplifier and in said second WLAN-compatible mode the dual-mode filter and amplifier is operable in said second WLAN-compatible mode and the feedback component is coupled between an input and an output port of said operational amplifier; said first feedback component including a resistor and a capacitor coupled to said first feedback component and said first switch; and the dual-mode filter and amplifier being responsive to the mode control signal through a plurality of switches to change the operation between the Bluetooth-compatible mode configuration and the second WLAN-compatible mode configuration so that: (i) during operation in the first Bluetooth-compatible mode the dual-mode filter and amplifier is configured as four-stage limiters with AC coupling, a first resistor and a bias current for the operational amplifier setting the amplitude of the limiters output, and a first capacitance C 1 and a second resistance R 2 setting the AC coupling high-pass corner frequency; and (ii) during the second WLAN-compatible mode the dual-mode filter and amplifier is configured as a four-stage voltage gain amplifier and the total gain range is set by the resistance ratio (R 4 /R 3 ) of a fourth resistance R 4 to a third resistance R 3 , and the four voltage gain amplifier stages are DC coupled.