摘要:
An adaptively tuned RF power amplifier includes at least one power amplifier stage that has one or more active elements. A tunable output network is coupled to the power amplifier stage and includes one or more adjustable reactive elements. A mismatch detector detects a tuning mismatch based, at least in part, on one or more signals present within the tunable output network, and supplies one or more mismatch signals indicative of a detected tuning mismatch. A tuning controller, responsive to the one or more mismatch signals, controls one or more of the one or more adjustable reactive elements in the tunable output network so as to control the detected mismatch.
摘要:
A bandpass delta sigma truncator receives a series of first multi-bit digital signals each having a number of data bits, a first number of sign bits and sign extending means for sign extending each of the first multi-bit digital signals to a second multi-bit digital signal having the same number of data bits as the number of data bits in the first multi-bit digital signals, and a second number of sign bits. The truncator outputs from a series of third multi-bit digital signals a series of fourth multi-bit digital signals each having a selected number of the most significant data bits of the third multi-bit digital signals, and a series of fifth multi-bit digital signals each having the remaining number of the least significant data bits of the third multi-bit digital signals.
摘要:
A sigma delta modulation device and method for filtering high frequency intermediate frequency signals. A summing amplifier receives the analog intermediate frequency signal, and provides to a surface acoustic wave filter (SAW) an analog signal which is to be converted to a digital quantity. A quantizer digitizes the signal to produce a digitized intermediate frequency signal. A digital to analog converter provides a feedback signal from the quantizer output signal, to the summing amplifier to form a sigma delta modulation device. The SAW filter provides for high stop band attenuation of signal images within the intermediate frequency signal, and produces a low noise signal with substantially no intermodulation products.
摘要:
A method includes controlling a mixer gain to provide a range of selected power output levels from the mixer using a first control scheme for a low portion of the range and using a second control scheme for a high portion of the range. Using the selected mixer gain, incoming baseband signals may be upconverted in the mixer to a transmission frequency and output from the mixer at the selected power output level.
摘要:
An adaptively tuned RF power amplifier includes at least one power amplifier stage that has one or more active elements. A tunable output network is coupled to the power amplifier stage and includes one or more adjustable reactive elements. A mismatch detector detects a tuning mismatch based, at least in part, on one or more signals present within the tunable output network, and supplies one or more mismatch signals indicative of a detected tuning mismatch. A tuning controller, responsive to the one or more mismatch signals, controls one or more of the one or more adjustable reactive elements in the tunable output network so as to control the detected mismatch.
摘要:
A technique includes storing in a memory a set of samples that are distorted so that the samples indicate a distorted representation of a modulation signal. The technique includes in response to the set of samples, generating a second signal that includes a substantially less distorted representation of the modulation signal. The distortion of the samples is used to at least partially compensate for a characteristic that is otherwise imparted to the second signal by the act of generating the second signal.
摘要:
A bandpass delta sigma truncator that truncates multi-bit digital input signals to digital output signals (24) having a selected number of the most significant data bits of the digital input signals and a method of truncating multi-bit digital signals. The remaining least significant data bits (3) of the input signals are (a) time delayed (26) by a period of time equal to the time between successive input signals and multiplied by a number (30) related to the ratio of a selected frequency to the frequency of the input signals and the results of the multiplication are added (32) to signs extensions (11) of the input signals, and (b) time delayed by a period of time equal to twice the time between successive input signals and after inversion (28) are added (32) to the sign extensions of the input signals.
摘要:
A bandgap circuit for producing a constant current having a controllable temperature coefficient. A current mirror supplies first and second substantially identical currents to first and second bipolar transistors. A first resistor is connected across the emitters of the bipolar transistors. A second resistor connects one to the bipolar emitters to a common terminal where the current source currents are recombined and supplied to a common terminal of a power supply. The band gap voltage produced at the common base connections of the bipolar transistors have a voltage temperature coefficient which is controlled by the values of the resistors. A current source is coupled to receive the bandgap voltage and produces a current having a temperature coefficient corresponding to the voltage temperature coefficient of the bandgap voltage.
摘要:
A digital to analog converter which produces a non-return to zero output voltage. Two SIN DAC converters having return to zero (RZ) output voltages connected to provide a common NRZ output signal. The SIN DAC converters receive the digital signal and a delayed version of the digital signal. The reference sine voltage applied to each SIN DAC have a respective phase shift so that the outputs from each SIN DAC are phase shifted. The combined phase shifted output signals produce an NRZ signal with a reduced susceptibility to clock signal jitter, and which contain significantly less high frequency content than the RZ output signal from a SIN DAC.
摘要翻译:一个产生不归零输出电压的数模转换器。 两个SIN DAC转换器返回零(RZ)输出电压,以提供公共的NRZ输出信号。 SIN DAC转换器接收数字信号和数字信号的延迟版本。 施加到每个SIN DAC的参考正弦电压具有相应的相移,使得来自每个SIN DAC的输出相移。 组合的相移输出信号产生具有对时钟信号抖动的敏感性降低的NRZ信号,并且其包含比来自SIN DAC的RZ输出信号显着更少的高频率内容。
摘要:
Embodiments may be used to control a controllable element that has a nonlinear but monotonic relationship with a control value. In such embodiments, a system may perform control by receiving an error value corresponding to an error of an output signal from the controllable element, and determining the control value within two iterations of a Newton (Secant) algorithm, where the control value enables generation of the output signal within a predetermined tolerance to a nominal value for the control signal.