摘要:
An estimation unit for estimating a nonlinearity error of a conversion circuit, such as an ADC, is adapted to receive a continuous-time input signal and output a digital output signal. In at least one embodiment, the continuous-time input signal is essentially bandlimited to an angular frequency band [ω1, ω2], where ω1>(L−1)π/T, ω2
摘要:
A filter comprises a stack of wafers (28). Each of the wafers has a through hole (6). Edges (7) of the holes together define an internal tube. An interface (32) between adjacent wafers defines filter channels. The filter channels comprises first coarse filter channels (20), second coarse filter channels (22) and fine filter channels (26). The first coarse filter channels are open towards an outer rim (5), extend in a direction from the outer rim and are closed towards the internal tube. The second coarse filter channels are arranged in an opposite manner. The fine filter channels connect the first and second coarse filter channels. The first and second coarse filter channels extend radially (R) and the fine filter channels extend tangentially (T). The first and second coarse filter channels are defined by recesses in a surface of a first wafer and the fine filter channels are defined by recesses, each one encircling the hole, in a surface of a second wafer.
摘要:
A method for the compensation of frequency-response mismatch errors in M-channel time-interleaved ADCs. The compensation is done through an M-periodic time-varying filter hn(k)=hn mod M(k) (2), or, equivalently, a set of M time-invariant filters hn(k), n=0, 1, . . . , M−1. The overall compensation system is constructed by determining the M filter impulse responses hn(k) through M separate matrix inversions, where the size of the matrices equals the filter impulse response length. Also, a compensated M-channel time-interleaved ADC based on and performing the method.
摘要:
A method for estimating a relative time difference vector in a group of digitized signals from a time interleaved analog-to-digital module having a plurality of parallel and time interleaved analog-to-digital converters. The method comprises the steps of selecting (S1) one of said digitized signals as a reference signal, calculating (S2-S3) an actual time delay between each of the remaining signals and said reference signal, and subtracting (S4), for each of said remaining signals, an intended interleaving time delay from said time delay. In order for this method to provide the correct estimate, the signal must be bandlimited, not only to the system bandwidth, but to the bandwidth of one ADC. However, given this bandwidth limitation, the estimation is very precise, and therefore enables reconstruction of the digitized signal without feedback.
摘要:
A method and a module for estimating a plurality of relative channel-error for at least one signal with respect to a reference signal. The signals and are produced by an analog-to-digital module including parallel and time interleaved analog-to-digital converters and are received by an estimation module. The method is performed by the estimation module and includes defining a function representing a relationship between the reference signal and an arbitrary signal in the group of signals, selecting a first reference signal in the group of signals, selecting a second signal from the remaining signals in the group, optimizing the function so as to obtain an estimate of the plurality of relative channel-error, and repeating the selecting a second signal and optimizing the function for each remaining signal.
摘要:
A vacuum unit, particularly for a vacuum toilet system, includes first and second valves (4, 6), an ejector (10) connected to the first valve, and a piston valve (16) which is connected between the ejector and the second valve. The unit is characterised in that an overpressure and a vacuum can both be generated from the first valve (4) by controlling the state of the piston valve by the combination of the states of the first and the second valves. A vacuum toilet system is also described.
摘要:
The present invention refers to a method and apparatus for reconstruction of a nonuniformly sampled bandlimited analog signal xa(t), said nonuniformly sampled signal comprising N subsequences xk(m), k=0, 1, . . . , N−1, N≧2, obtained through sampling at a sampling rate of 1/(MT) according to xk(m)=xa(nMT+tk), where M is an integer, and tk=kMT/N+&Dgr;tk, &Dgr;tk being different from zero. The invention comprises forming a new sequence y(n) from said N subsequences xk(m) such that y(n) at least contains the same information as x(n)=xa(nT), i.e. xa(t) sampled with a sampling rate of 1/T, in a frequency region lower than &ohgr;0, &ohgr;0 being a predetermined limit frequency, by means of (i) upsampling each of said N subsequences xk(m), k=0, 1, . . . , N−1, by a factor M, M being a positive integer; (ii) filtering each of said upsampled N subsequences xk(m), k=0, 1, . . . , N−1, by a respective digital filter; and (iii) adding said N digitally filtered subsequences to form y(n). The respective digital filter is preferably a fractional delay filter and has preferably a frequency response Gk=ake(−j&ohgr;sT), k=0, 1, . . . , N−1, in the frequency band |&ohgr;T|≦&ohgr;0T, ak being a constant and s=d+tk, d being an integer.
摘要:
Methods for compensation of imbalance between I (In-phase) and Q (Quadrature) signal paths (12a, 12b, 605a, 605b) in a quadrature receiver (8) and a quadrature transmitter (600) are disclosed. In the receiver case, the imbalance is compensated for by means of post-distortion in the digital domain. In the transmitter case, the imbalance is compensated for by means of pre-distortion in the digital domain. The methods can be carried out with a relatively low computational complexity. Signal-processing devices (30, 610) for carrying out the methods are disclosed as well. The same basic internal structure may be used for the signal-processing device (30) in the receiver case as for the signal processing device (610) in the transmitter case.
摘要:
An estimation unit for estimating a nonlinearity error of a conversion circuit, such as an ADC, is adapted to receive a continuous-time input signal and output a digital output signal. In at least one embodiment, the continuous-time input signal is essentially bandlimited to an angular frequency band [ω1, ω2], where ω1>(L−1)π/T, ω2
摘要:
Device for measuring the bottom of vehicles comprising an extendable rule that in one end is provided with a conical mandrel for contact with measuring holes or points and that the ruler in its other end is provided with a magnetic fastening means and a centering means for centering the fastening means relative to holes in the bottom. The centering means is a conical mandrel that against the force of a spring can be pushed into the fastening bracket.