Abstract:
An analog-to-digital (A/D) converter circuit arranged for receiving an analog input signal and for outputting a digital representation of said analog input signal is described. The A/D converter circuit includes: a first converter stage configured for receiving the analog input signal and for generating a first set of conversion bits, a first completion signal and a residual analog output signal representing the difference between the analog input signal and a signal represented by said first set of conversion bits, a second converter stage comprising a clock generation circuit arranged for receiving the first completion signal and for generating a clock signal, a plurality of comparators each being configured for receiving the residual analog output signal and a common reference voltage, said plurality of comparators arranged for being activated by the clock signal and for outputting a plurality of comparator decisions, a digital processing stage configured for receiving the plurality of comparator decisions and for generating a second set of conversion bits, means for generating the digital representation of the analog input signal by combining the first and second set of conversion bits.
Abstract:
The invention relates to a voltage controlled oscillator for generating a variable frequency. The oscillator comprises an oscillator core and a transconductive portion for compensating current losses in the oscillator core. The oscillator core comprises an inductive portion with at least one inductive element and a capacitive portion whose capacitance can be continuously varied by means of a control voltage for varying said frequency. The capacitive portion comprises multiple variable capacitive elements whose capacitance is continuously variable by means of said control voltage, each variable capacitive element being switchable for being added to or removed from the capacitive portion.
Abstract:
A device and a method are presented for generating an intermitted oscillating signal comprising a plurality of oscillating portions separated from each other in time. The device and method are suited for communication systems, in particular for Ultra-Wide Bandwidth (UWB) applications. The device comprises a variable oscillator for generating the oscillating portions; switching circuitry for switching on/switching off the variable oscillator at the beginning/end of each oscillating portion; and circuitry for setting initial conditions in the variable oscillator to impose a predefined transient and a characterizing frequency upon each start-up.
Abstract:
An electrical device comprises analog conversion circuitry having an input and an output. The electrical device is essentially provided for converting a first input signal within a first frequency range applied to the input to a first output signal within a second frequency range different from the first frequency range at the output. The electrical device further comprises a signal adding means for adding at least a portion of the first output signal as second input signal to the first input signal. The analog conversion circuitry is also capable of converting the second input signal, which is within the second frequency range, back to the first frequency range. Additionally, a characteristic deriving means is provided for deriving at least one characteristic of the electrical device from the frequency converted second input signal, which appears at the output of the analog conversion circuitry.
Abstract:
A signal generator for generating signals that are spaced π/X rad apart, where X is an integer. The signal generator includes at least one delay cell with a delay that approximately corresponds to a phase shift π/X rad for a given signal. The signal generator also includes at least one phase detection system receiving at least two signals with a phase difference of approximately π/2 rad with respect to one another from said at least one delay cell and generating a feedback signal that is communicated to the at least one delay cell to adjust the phase relationship of the at least two signals. Such signal generators are used in radio frequency up-converters or down-converters.
Abstract:
An analog-to-digital (A/D) converter circuit arranged for receiving an analog input signal and for outputting a digital representation of said analog input signal is described. The A/D converter circuit includes: a first converter stage configured for receiving the analog input signal and for generating a first set of conversion bits, a first completion signal and a residual analog output signal representing the difference between the analog input signal and a signal represented by said first set of conversion bits, a second converter stage comprising a clock generation circuit arranged for receiving the first completion signal and for generating a clock signal, a plurality of comparators each being configured for receiving the residual analog output signal and a common reference voltage, said plurality of comparators arranged for being activated by the clock signal and for outputting a plurality of comparator decisions, a digital processing stage configured for receiving the plurality of comparator decisions and for generating a second set of conversion bits, means for generating the digital representation of the analog input signal by combining the first and second set of conversion bits.
Abstract:
Transmitter circuits for generating baseband signals having low receiver-band noise are disclosed. In one embodiment, the transmitter circuit comprises an active filtering-and-amplifying component comprising a first input configured to receive a first input signal, and a first output configured to output a first output signal. The transmitter circuit further comprises a passive filtering component comprising a second input connected to the first output and configured to receive the first output signal, a passive pole arrangement comprising a number of switchable resistance elements and a capacitance element connected across the plurality of switchable resistance elements, and a second output configured to output a second output signal having reduced noise as compared to the first output signal. The transmitter still further comprises a number of feedback loops connecting the passive filtering component to the first input.
Abstract:
An electrical device comprises analog conversion circuitry having an input and an output. The electrical device is essentially provided for converting a first input signal within a first frequency range applied to the input to a first output signal within a second frequency range different from the first frequency range at the output. The electrical device further comprises a signal adding means for adding at least a portion of the first output signal as second input signal to the first input signal. The analog conversion circuitry is also capable of converting the second input signal, which is within the second frequency range, back to the first frequency range. Additionally, a characteristic deriving means is provided for deriving at least one characteristic of the electrical device from the frequency converted second input signal, which appears at the output of the analog conversion circuitry.
Abstract:
The invention relates to a voltage controlled oscillator for generating a variable frequency. The oscillator comprises an oscillator core and a transconductive portion for compensating current losses in the oscillator core. The oscillator core comprises an inductive portion with at least one inductive element and a capacitive portion whose capacitance can be continuously varied by means of a control voltage for varying said frequency. The capacitive portion comprises multiple variable capacitive elements whose capacitance is continuously variable by means of said control voltage, each variable capacitive element being switchable for being added to or removed from the capacitive portion.
Abstract:
An analog to digital conversion circuit and method is presented. The analog to digital circuit (100) comprises a first capacitor (103), arranged for being switchably (102) connected on one side to an input voltage (101), at least one successive approximation circuit (104), a comparator (108) arranged for outputting a sign indicative of the difference between the voltage on the first capacitor (103) and a comparison voltage (109), and a control block (110), arranged for converting said comparator's output into steering signals and in a digital output signal. The successive approximation circuit comprises a second capacitive structure (106), switchably connected to a pre-charge circuit (107) arranged for pre-charging the second capacitive structure (106), whereby the second capacitive structure (106) is connected in parallel with the first capacitor (103) via a charge copying circuit (105). The steering signals comprise of a signal for steering (112) said charge copying circuit (105) and for steering (113) the pre-charge circuit (107).