A 5-GHz combined oscillator/mixer

Abstract

In this paper an IQ oscillator/mixer circuit is presented in which the mixers are an integral part of the oscillator. The oscillator alone has accurate quadrature outputs, even in the presence of component mismatch. This precise quadrature is preserved when mixers are incorporated in the oscillator. An oscillator/mixer core for a carrier frequency of 5 GHz, suitable for a low-IF front-end, was designed and tested. The power consumption is 30 mW from a 2.5 V supply, and a phase error of 1º was measured.

A 2.41 GHz ISM receiver using an IQ VCO-mixer

“…The IQ VCO-mixer is based on an IQ cross-coupled RC relaxation VCO, where two single oscillators are coupled through active loads. A topology that consumes less power and reduces the area, in comparison to the commonly used soft-limiter coupling [1] [2]. Furthermore, the incorporation of the mixing function on the VCO benefits from an increased gain, while reusing the same block.…”

A 5 GHz quadrature relaxation oscillator with mixing for improved testability or compact front‐end implementation

“…In this paper we consider an RC cross-coupled relaxation oscillator and we show that the precise quadrature [7] is preserved when mixing is incorporated in the oscillator [8,9]. This approach avoids the need for separate mixers, whose mismatches would be responsible for a first-order error.…”