Motorola Corporation

Andrew Gerald Zocher

Mahibur Rahman

Joseph P Heck

Sumit Anil Talwalkar

Timothy Keith Coffman

A transmit path correction system () for compensating for digital DC offsets, I/Q gain imbalances and I/Q phase imbalances includes a mixed signal forward path () and a mixed signal feedback path (). The forward pat (), which is operable to process input data symbols to produce at least one analog output signal, preferably includes a digital DC offset correction circuit () for compensating for digital DC offsets in the forward path () using at least one digital feedback signal (), an I/Q phase equalization circuit () for compensating for the I/Q phase imbalances in the forward path (), and an I/Q gain equalization circuit () for compensating for the I/Q gain imbalances in the forward path () using the digital feedback signal(s) (). The feedback pat () processes the analog output of the forward path () to produce the digital feedback signal(s) ().

Self calibrating transmit path correction system

A variable gain control circuit ( ) includes a programmable operational transconductance amplifier (OTA) circuit ( ) and a programmable conveying circuit ( ). The conveying circuit ( ) has a programmable differential circuit ( ) interconnected to a pair of programming inputs ( ). The pair of programming inputs ( ) is interconnected to a pair of programming inputs ( ) that set the gain of the OTA circuit ( ). When the OTA circuit ( ) is configured as an operational transconductance filter ( ), the programmable differential circuit ( ) can adjust the gain of the conveying circuit ( ) to compensate for changes in the input impedance of the filter ( ). The programming inputs ( ) that set the input impedance and bandwidth of the filter ( ) also control the amount of signal current transmitted by the conveying circuit ( ).

Variable gain control circuit for a receiver and method therefor

An amplifier circuit (204) having a variable bandwidth comprises an amplifier (300), a capacitive element (304), a first npn transistor (302), and a switch control circuit (306). The first npn transistor (302) has a base coupled to an output terminal (205) of the amplifier (300), a collector coupled to a first reference voltage (113), and an emitter coupled to the capacitive element (304) and the switch control circuit (306). When the first npn transistor (302) is switched off by the switch control circuit (306), a first cutoff frequency is determined by a maximum operating frequency of the amplifier (300). When the first npn transistor (302) is switched on by the switch control circuit (306), a second cutoff frequency is determined by a capacitance of the capacitive element (304). For high frequency operation, the amplifier (300) includes at least a second npn transistor for amplification and the first cutoff frequency is determined by a Miller capacitance of the amplifier circuit (204).

Amplifier circuit having a variable bandwidth

An electronic circuit (412) comprises a biasing circuit (414) and an amplifier (416). Biasing circuit (414) biases amplifier (416) with a first current when a supply voltage of electronic circuit (412) is within a predetermined voltage range corresponding to a first supply voltage, and biases amplifier (416) with a second current when the supply voltage is within a predetermined voltage range corresponding to a second supply voltage. The first current and the second current provide separate operating points for amplifier (416), operating points which may, upon design, provide substantially the same operating characteristics. The operating points change with the supply voltage in order to minimize power dissipation. Electronic circuit (412) is suitable for use in an integrated circuit, where it can be used in various electronic systems which provide different supply voltages or have a potential for using lower-voltage technology in the future.

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Spring Grove, IL, United States of America

Andrew Gerald Zocher