Abstract:
To avoid damage from overheating, playback device operation can be modulated based on input from temperature sensors. An example method includes obtaining, via one or more temperature sensors carried by the playback device, temperature data. Based on the temperature data, a first temperature parameter is detected. In response to detecting the first temperature parameter, a gain of audio playback is decreased by a first amount. After decreasing the gain of audio playback by the first amount, a second temperature parameter is detected. In response to detecting the second temperature parameter, the gain of audio playback is decreased by a second amount different than the first amount.
Abstract:
An amplifier circuit comprises a detection power input circuit for receiving an RF signal, and a bias circuit that includes an output for generating a bias signal in response to a reference control voltage. The power detector further comprises a detection circuit for generating a power control voltage having a voltage characteristic that offsets temperature characteristics of the received RF signal. The amplifier circuit further comprises a power amplifier coupled to the bias circuit. The power amplifier includes a driver stage providing the RF signal. The detection circuit compensates temperature variation of the inputted detection voltage of the received RF signal.
Abstract:
The present invention relates to radio transmission of bursts in for example a TDMA cellular radio system. The burst starts with a ramping up period, ends with a corresponding ramping down ramping down period and with the pay-load information therebetween. The ramp form is created in a ramp generator (13) which gives a multiplication value to multiply the digital information to be transmitted in multipliers (15, 16). The multiplied values are converted into analogue form and amplified before being transferred to the antenna (21). Output power and temperature of the transmitting equipment are measured (22, 23) and used to update the output power levels during the next burst.
Abstract:
A power amplifier can include an input stage that includes an amplifying transistor having an input node and an output node, such that a signal at the input node has a first power level and an amplified signal at the output node has a second power level. The power amplifier can further include a bias circuit configured to provide a bias signal to the amplifying transistor, and a feedback circuit that couples the output node of the amplifying transistor to the input node of the amplifying transistor. The feedback circuit can include a resistance and a capacitance arranged in series. The power amplifier can further include a gain compensation circuit implemented relative to the input stage such that the second power level is compensated for a variation in temperature associated with the power amplifier.
Abstract:
To avoid damage from overheating, playback device operation can be modulated based on input from temperature sensors. An example method includes obtaining, via one or more temperature sensors carried by the playback device, temperature data. Based on the temperature data, a first temperature parameter is detected. In response to detecting the first temperature parameter, a gain of audio playback is decreased by a first amount. After decreasing the gain of audio playback by the first amount, a second temperature parameter is detected. In response to detecting the second temperature parameter, the gain of audio playback is decreased by a second amount different than the first amount.
Abstract:
An amplifier circuit comprises a detection power input circuit for receiving an RF signal, and a bias circuit that includes an output for generating a bias signal in response to a reference control voltage. The power detector further comprises a detection circuit for generating a power control voltage having a voltage characteristic that offsets temperature characteristics of the received RF signal. The amplifier circuit further comprises a power amplifier coupled to the bias circuit. The power amplifier includes a driver stage providing the RF signal. The detection circuit compensates temperature variation of the inputted detection voltage of the received RF signal.
Abstract:
A transmission power control apparatus which reduces the number of steps required for adjustments of the transmission power control apparatus and performs transmission power control with high accuracy in a wide dynamic range. The apparatus has a first variable amplifying circuit (122) with the resolution of 1 dB and a second variable amplifying circuit (123) with the resolution of 0.1 dB, where a correction value calculating section (106) calculates a correction value to compensate for deterioration in the accuracy of transmission power caused by a change in environment due to frequency characteristics and temperature characteristics and another correction value to compensate for error in transmission power, a transmission power calculating section (107) calculates transmission power obtained by correcting with the correction value specified transmission power to output to a communicating party based on the received signal, and a first set value calculating section (108) and a second set value calculating section (109) calculate gain values to set on the first variable amplifying circuit (122) and second variable amplifying circuit (123) based on the corrected transmission power, respectively.
Abstract:
A temperature compensation circuit comprises a temperature coefficient circuit that generates a temperature coefficient that is temperature dependent and a compensation circuit that generates a compensation signal based on an indication of temperature of an amplifier and the temperature coefficient, and based on the compensation signal, a gain of the amplifier is adjusted to improve amplifier linearity during data bursts.
Abstract:
A programmable gain amplifier comprises a current source that generates a first current based on a first transfer function. A voltage amplifier receives an input voltage signal and generates an output voltage signal based on a gain A, wherein the gain A is based on a control current and a second transfer function. A compensation module generates the control current based on the first current and a mapping function, wherein the mapping function is based on the first transfer function and the second transfer function to reduce the effect of an independent variable on an overall transfer function that relates the first current to the gain A.
Abstract:
A compensated control circuit includes a combination module that generates a control variable based on n signals and a process module that generates an output signal based on an input signal and the control variable wherein n is a positive integer.