摘要:
An oscillator circuit (100) provides improved noise immunity by utilizing a differential common base configuration. The oscillator includes a differential transistor pair (102, 104) having common bases (110) coupled through an AC ground (108) and emitters coupled through a differential common mode point (120). First and second resonant tank circuits are each referenced to the differential common mode point (120) for generating a differential output (OUT, OUTX).
摘要:
A prescaler (100) includes a frequency divider (102) having an input node (136) and a divider output (128). The frequency divider is coupled to a clock signal and has a predetermined divisor. Series-coupled delay elements (104, 106, 108) are coupled to the divider output and to the clock signal. Each delay element includes a delayed output (130, 132, 134) and adds a delay equal to the clock period at the delayed output. The prescaler also includes transmission gates (112, 114, 116), each transmission gate coupled between the input node and the delayed output of a corresponding one of the delay elements. When one of the transmission gates is enabled and couples the delayed output of an nth one of the delay elements to the input node, the divider output frequency equals the clock frequency divided by the predetermined divisor plus n.
摘要:
A signal generation power management control system (100) for use in a portable communications device includes a digital signal processor (DSP) (101) for processing a digital source input and providing a digital processed bit stream A digital-to-analog converter (DAC) (103) is used for converting the digital processed bit stream to provide an analog signal. A power management controller (115) within the DSP (101) is then used for interpreting control parameters of signal processing components used within the portable communications device and dynamically adjusting the bias current of these components based on minimal signal requirements of the analog signal.
摘要:
A signal generation power management control system (100) for use in a portable communications device includes a digital signal processor (DSP) (101) for processing a digital source input and providing a digital processed bit stream A digital-to-analog converter (DAC) (103) is used for converting the digital processed bit stream to provide an analog signal. A power management controller (115) within the DSP (101) is then used for interpreting control parameters of signal processing components used within the portable communications device and dynamically adjusting the bias current of these components based on minimal signal requirements of the analog signal.
摘要:
A programmable voltage controlled attenuator (100) meets the dynamic range and gain requirements for various communication protocols using a single bias generator circuit (104). A control voltage input, Vcnt, and a slope select input provide the dynamic range and attenuation for a voltage controlled attenuator (VCA) (109.).
摘要:
A programmable voltage controlled attenuator (100) meets the dynamic range and gain requirements for various communication protocols using a single bias generator circuit (104). A control voltage input, Vcnt, and a slope select input provide the dynamic range and attenuation for a voltage controlled attenuator (VCA) (102).