Innophase Inc.

Xuejun Zhang

Yang Xu

Nicolo Testi

Xi Li

A DAC using current mirrors suitable for use in a modulator. Embodiments include a current-generating circuit to provide an information signal; a bias current source; a current mirror having a mirror input transistor connected to the current generating circuit and the bias current source, and being driven by the bias current and the varying current signal and having a corresponding varying voltage signal at a control terminal; a signal shaping filter interposed between the mirror input transistor and an output mirror transistor configured to limit a bandwidth of the varying voltage signal; the output mirror transistor configured to generate a band-limited varying current signal and a mirrored bias current; and, a mirrored bias current reduction circuit connected to the output mirror transistor configured to reduce the mirrored bias current.

Apparatus and method for digital to analog conversion with current mirror amplification

Single-bit transmitter modulator having a digital pulse shaping filter configured to shape data pulses of an inphase signal and quadrature signal; an upsampling filter configured to increase the sample rate of the inphase signal and quadrature signal; a sigma-delta modulator providing a one-bit inphase output signal and a one-bit quadrature output signal; an inphase low-order analog low pass filter coupling the one-bit inphase output signal to an inphase channel input of a quadrature modulator, and a quadrature low-order analog low pass filter coupling the one-bit quadrature output signal to a quadrature channel input of a quadrature modulator; and, wherein the quadrature modulator is connected to a carrier signal generator and is configured to generate an inphase and quadrature modulated carrier.

Single-bit direct modulation transmitter

A low noise amplifier including a variable gain amplifier stage configured to accept an input signal and to provide a load driving signal; a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component when the load driving signal is of a magnitude large enough to decreases a transconductance of the cross-coupled transistor pair; and, a controller circuit configured to tune the bandpass filter. The filter can be tuned in respect to the frequency and the quality factor Q.

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Chicago, IL, United States of America

Xuejun Zhang