A radio transmitter includes a power amplifier configured to receive an input voltage signal and output an output voltage signal; a transformer configured to receive the output voltage signal and output a load voltage signal to a load; a sensing inductor configured to output a sensed current signal in accordance with a magnetic coupling with the transformer; a digitally controlled phase shifter configured to receive the output voltage signal and output a phase-shifted voltage signal in accordance with a phase control code; a mixer configured to output a mixed current signal in accordance with a mixing of the sensed current signal and the phase-shifted voltage signal; and a transimpedance amplifier with of a low-pass response configured to convert the mixed current signal into a mean voltage signal.

Temperature compensation circuits and methods for adjusting one or more circuit parameters of a power amplifier (PA) to maintain approximately constant Gain versus time during pulsed operation sufficient to substantially offset self-heating of the PA. Some embodiments compensate for PA Gain droop due to self-heating using a Sample and Hold (S&H) circuit. The S&H circuit samples and holds an initial temperature of the PA at commencement of a pulse. Thereafter, the S&H circuit generates a continuous measurement that corresponds to the temperature of the PA during the remainder of the pulse. A Gain Control signal is generated that is a function of the difference between the initial temperature and the operating temperature of the PA as the PA self-heats for the duration of the pulse. The Gain Control signal is applied to one or more adjustable or tunable circuits within a PA to offset the Gain droop of the PA.

Apparatus and methods for non-invasively monitoring an oscillation signal in an effort to provide a more reliable oscillation signal. An example oscillation circuit generally includes an oscillator configured to generate an oscillation signal, the oscillator comprising an oscillator core circuit for coupling to a resonator and configured to generate the oscillation signal to enable the resonator to resonate and an adjustable current source coupled to the oscillator core circuit and configured to control an amplitude of the oscillation signal; a first automatic gain control (AGC) circuit having an input coupled to an output of the oscillator and having an output coupled to a control input of the adjustable current source; a second AGC circuit configured to replicate the first AGC circuit; and logic having a first input coupled to the output of the first AGC circuit and having a second input coupled to an output of the second AGC circuit.

Automatic Gain Control (AGC) system for multi-channel signals attenuates an incoming multi-channel signal by providing a gain. The system further adjusts each individual channel, of the multi-channel signal, by supplying a second gain if needed. The AGC system is designed to ensure a received signal power is at an optimal level for analog to digital conversion or any other form of signal processing. The system also enables elimination of mid-packet gain adjustments.

A plasma processing apparatus 10 includes a chamber 17 in which an internal space is provided and a target object carried into the internal space is processed with plasma in the internal space; a high frequency power source 14 configured to supply a high frequency power for plasma generation within the chamber 17; a matching circuit 15 configured to match an impedance of the plasma within the chamber 17 with an impedance of the high frequency power source 14; a signal synchronizer 20 configured to calculate the impedance of the plasma within the chamber 17; a control amount calculator 12 configured to control a frequency and a magnitude of the high frequency power, and an impedance of the matching circuit 15 based on the impedance calculated by the signal synchronizer 20. Further, the signal synchronizer 20 and the control amount calculator 12 are provided on a single substrate 11.

An apparatus for detecting a neural spike includes: a preprocessing circuit configured to remove a low-frequency component from a neural signal to form a low-frequency component removed neural signal, and amplify the low-frequency component removed neural signal; a comparing circuit configured to compare an output signal of the preprocessing circuit to a threshold signal; a merging circuit configured to merge spikes within a reference interval of an output signal of the comparing circuit into one peak, and to generate, based on the merging of the spikes, an output signal comprising pulses; and a counting circuit configured to count the pulses.

A method of controlling bandwidth and peaking over gain in a variable gain amplifier (VGA) device and structure therefor. The device includes at least three differential transistor pairs configured as a cross-coupled differential amplifier with differential input nodes, differential bias nodes, differential output nodes, a current source node, and two cross-coupling nodes. The cross-coupled differential amplifier includes a load resistor coupled to each of the differential output nodes and one of the cross-coupling nodes, and a load inductor coupled to the each of the cross-coupling nodes and a power supply rail. A current source is electrically coupled to the current source node. The cross-coupling configuration with the load resistance and inductance results in a lower bandwidth and lowered peaking at low gain compared to high gain. Further, the tap point into the inductor can be chosen as another variable to tune the bandwidth and peaking in a communication system.

Wideband signal buffers that can be employed for mmWave (millimeter wave) communication are disclosed. One example signal buffer comprises a variable gain amplifier (VGA) that receives two control words and outputs a feedback signal, wherein both an amplitude and a phase of the feedback signal are based on the two control words and on a bias voltage; and a matching network comprising a first inductor that outputs the bias voltage, a second inductor, and a third inductor that receives the feedback signal from the VGA, and wherein the first, second, and third inductors are magnetically coupled to each other, wherein the signal buffer is configured to receive a RF (Radio Frequency) input and to generate a RF output from the RF input based on a transfer function of the signal buffer, wherein the transfer function is based at least in part on the feedback signal.

Systems and methods for operating a communication device so as to mitigate intermodulation interference to a signal. The methods comprise: continuously monitoring several communication channels by the communication device; using a noise floor level estimate of the communication device to detect when the communication device is under an influence of hig interference; determining an optimal level of attenuation to be applied by a variable attenuator of the communication device's receiver so as to mitigate the influence of intermodulation interference to the signal; and selectively adjusting an amount of attenuation being applied by the variable attenuator to achieve the optimal level of attenuation for mitigating intermodulation interference.

A power amplifier circuit includes a first transistor that amplifies an RF signal; a bias current source that supplies a bias current to a second terminal of the first transistor through a first current path; and an adjustment circuit that adjusts the bias current in accordance with a variable power-supply voltage supplied from a power-supply terminal. The adjustment circuit includes first to third resistors, and an adjustment transistor including a first terminal connected to the power-supply terminal through the first resistor, a second terminal connected to the bias current source through the second resistor, and a third terminal connected to the first current path through the third resistor. When the variable power-supply voltage is not less than a first voltage and not greater than a third voltage, the adjustment circuit increases a current that flows to the power-supply terminal through a second current path as the variable power-supply voltage decreases.