Abstract: An improved receiver architecture and method for a wireless transceiver (e.g. for a headphone) is provided whereby the receiver, advantageously, enables the use of only one synthesizer circuit for both the RF-to-IF and IF-to-base band conversion processes which, in turn, provides for lower power consumption. The receiver includes an injection locked local receiver oscillator (Rx LO) which is used for the first mixing stage (i.e. the RF-to-IF conversion). The Rx LO 105 is thereby able to use a high-level harmonic of a relatively low reference frequency signal produced by that synthesizer (e.g. a fractional-N phase locked loop circuit (PLL)). The receiver further includes a tunable Q-enhanced IF filter 110 and complex sub-sampling and mixing down-conversion circuitry for the second conversion stage (i.e. IF-to-baseband conversion). The sampling frequency used for the second conversion stage is a harmonic of the reference frequency derived from the synthesizer (PLL).

Abstract: A method and system for reducing local oscillator leakage from radio frequency mixers is disclosed. Compensating circuits are used to reduce or eliminate unwanted leakage from the mixer output signal by controlling the current in individual branches of a balanced input circuit of the mixer. The current is directly controlled by adjusting the voltage on the bases of the differential type amplifier input transistors, or by injecting current directly into the individual branches, or by extracting current directly from the individual branches. The current is also indirectly controlled by increasing the temperature of the mixer components with power dissipation elements that are not connected to the mixer. The compensating circuits are made of different combinations of resistor, transistor and current sink components.

Abstract: A voltage controlled oscillator has a cross-coupled negative resistance cell formed as an integrated circuit connected to off-chip components of a high-Q resonant tank circuit. To counteract spurious oscillations brought about by package parasitics caused by the interconnection of the chip to the external components, the cell is provided with a degeneration impedance. Typically, a pure inductor is used if all the elements of the tank circuit are off-chip. In a case where the tank circuit includes an on-chip fixed capacitor, the degeneration impedance may take the form of a capacitor.