Built-in self-test systems and methods for integrated circuit baseband quadrature modulators

Abstract

Integrated circuit transmit modules include an integrated circuit substrate, a baseband I/Q modulator in the integrated circuit substrate that modulates an input signal to produce in-phase (I) and quadrature (Q) baseband modulated inputs, and a built-in self-test (BIST) module in the integrated circuit substrate that monitors the I and Q baseband modulated outputs, to determine whether the baseband I/Q modulator is operating properly. The BIST module generates test input data for the baseband I/Q modulator. Alternatively or in addition, the BIST module can monitor the I and Q baseband modulated outputs in response to a communications input signal from a digital signal processor. The BIST module can generate a status signal to indicate whether the baseband I/Q modulator is operating properly. The BIST module includes a first filter that is responsive to the input signal to produce a filtered input signal and a second filter that is responsive to the I and Q baseband modulated outputs, to produce a filtered output signal. A compare module compares the filtered input signal and the filtered output signal. A phase and amplitude adjuster adjusts the phase and/or amplitude of the output of the first filter. Accordingly, modulators are tested prior to and/or during field use.