Abstract: Techniques for providing low-cost and effective jammer rejection for a radio receiver. In an aspect, a notch filter is provided between a transformer and a differential mixer in the receiver. The notch frequency of the notch filter may be selected to correspond to an expected jammer frequency to effectively attenuate the jammer signal prior to down-conversion mixing by the mixer. The notch filter may be implemented using various techniques, e.g., an L-C combination having adjustable capacitance, and/or elliptic or Chebyshev filters.

Abstract: Techniques for routing and shielding signal lines to improve isolation between the signal lines are disclosed. In an exemplary design, an apparatus includes first, second, and third signal lines and a switch. The first, second, and third signal lines are configurable to carry first, second, and third signals, respectively. The switch is coupled between the second signal line and AC ground and is closed when the second signal line is not carrying the second signal. The second signal line isolates the first and third signal lines when the switch is closed. Adjacent signal lines are not active at the same time. A signal line may include positive and negative signal lines, which may have at least one cross over in order to cancel coupling between the positive and negative signal lines.

Abstract: Split amplifiers with configurable gain and linearization circuitry are disclosed. In an exemplary design, an apparatus includes first and second amplifier circuits and a linearization circuit, which may be part of an amplifier. The first and second amplifier circuits are coupled in parallel and to an amplifier input. The linearization circuit is also coupled to the amplifier input. The first and second amplifier circuits are enabled in a high-gain mode. One of the first and second amplifier circuits is enabled in a low-gain mode. The linearization circuit is enabled in the second mode and disabled in the first mode. The amplifier is split into multiple sections. Each section includes an amplifier circuit and is a fraction of the amplifier. High linearly may be obtained using one amplifier circuit and the linearization circuit in the low-gain mode.

Abstract: Amplifiers with inductive degeneration and configurable gain and input matching are disclosed. In an exemplary design, an apparatus includes a gain transistor, an inductor, and an input matching circuit for an amplifier. The gain transistor has a variable gain determined based on its bias current. The inductor is coupled between the gain transistor and circuit ground. The input matching circuit is selectively coupled to the gain transistor based on the variable gain of the gain transistor. For example, the input matching circuit may be coupled to the gain transistor in a low-gain mode and decoupled from the gain transistor in the high-gain mode. In an exemplary design, the input matching circuit includes a resistor, a capacitor, and a second transistor coupled in series. The resistor is used for input matching of the amplifier. The second transistor couples or decouples the resistor to or from the gain transistor.

Abstract: Multi-output amplifiers with configurable source degeneration inductance and having good performance are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes a gain transistor and a configurable degeneration inductor for an amplifier. The gain transistor receives an input signal and provides an amplified signal. The amplifier provides a single output signal in a first operating mode or a plurality of output signals in a second operating mode. The configurable degeneration inductor is coupled to the gain transistor and provides a first source degeneration inductance in the first operating mode or a second source degeneration inductance in the second operating mode. The second source degeneration inductance is less than the first source degeneration inductance and may be dependent on the number of output signals generated in the second operating mode.

Abstract: A process for recovery of materials from a mother liquor residue comprising cracking a mother liquor residue with an aromatic sulfonic acid catalyst to form a cracked product mixture and separating phenol from the cracked product mixture wherein the mother liquor residue results from distillation of a mother liquor resulting from bisphenol A synthesis and isolation.