Abstract:
The invention relates to a time-continous FIR (Finite Impulse Response) filter whereby a Hilbert transform can be implemented. The filter comprises a cascade of delay cells connected between an input terminal of the filter and an output terminal; constant filter coefficients (cO,...,cn) and a programmable time delay (Td) of the programmable filter cells are provided. The invention also relates to a filtering method effective to enable use of this Hilbert FIR filter structure for processing signals originated by the reading of data from magnetic storage media which employ perpendicular recording.
Abstract:
This invention relates to a circuit structure of the feedforward type with programmable zeroes, particularly for synthesizing time-continual filters. This structure comprises a pair of amplification cells (14,15) interconnected at at least one interconnection node (A) and connected between a first signal (Vin) input (IN) of a first cell (14) and an output terminal (U) of the second cell (15, each cell (14,15) comprising a pair of transistors (10,2;6,7) which have a conduction terminal in common and have the other conduction terminals coupled respectively to a first voltage reference (Vcc) through respective bias members (3,4;9,11). The structure further comprises a circuit leg (13) connecting a node (X) of the first cell (14) to the output terminal (U) and comprising a transistor (8) which has a control terminal connected to the node (X) of the first cell (14), a first conduction terminal connected to the output terminal (U), and a second conduction terminal coupled to a second voltage reference (GND) through a capacitor (Cc). Thus, a released "zero" can be introduced in the right semiplane of the pole-zero complex plane to improve the flattening of group gain.
Abstract:
The invention relates to a low supply voltage analog multiplier which comprises a pair of differential cells (10,11), each cell comprising a pair of bipolar transistors (2,3;6,7) with coupled emitters. A first transistor (2,6) of each cell (10,11) receives an input signal (Vin+,Vin-) on its base terminal and has its collector terminal coupled to a first voltage reference (Vcc) through a bias member (4,8). Advantageously, the second transistor (3,7) of each cell is a diode configuration, and the cells are interconnected at a common node (A) corresponding to the base terminals of the second transistors (3,7) in each pair. This multiplier can be supplied very low voltages and still exhibit a high rate of operation along with reduced harmonic distortion of the output signal, even with input signals of peak-to-peak amplitude above 600 mV.
Abstract:
This invention relates to a circuit structure of the feedforward type with programmable zeroes, particularly for synthesizing time-continual filters. This structure comprises a pair of amplification cells (14,15) interconnected at at least one interconnection node (A) and connected between a first signal (Vin) input (IN) of a first cell (14) and an output terminal (U) of the second cell (15, each cell (14,15) comprising a pair of transistors (10,2;6,7) which have a conduction terminal in common and have the other conduction terminals coupled respectively to a first voltage reference (Vcc) through respective bias members (3,4;9,11). The structure further comprises a circuit leg (13) connecting a node (X) of the first cell (14) to the output terminal (U) and comprising a transistor (8) which has a control terminal connected to the node (X) of the first cell (14), a first conduction terminal connected to the output terminal (U), and a second conduction terminal coupled to a second voltage reference (GND) through a capacitor (Cc). Thus, a released "zero" can be introduced in the right semiplane of the pole-zero complex plane to improve the flattening of group gain.
Abstract:
The invention relates to a low supply voltage analog multiplier which comprises a pair of differential cells (10,11), each cell comprising a pair of bipolar transistors (2,3;6,7) with coupled emitters. A first transistor (2,6) of each cell (10,11) receives an input signal (Vin+,Vin-) on its base terminal and has its collector terminal coupled to a first voltage reference (Vcc) through a bias member (4,8). Advantageously, the second transistor (3,7) of each cell is a diode configuration, and the cells are interconnected at a common node (A) corresponding to the base terminals of the second transistors (3,7) in each pair. This multiplier can be supplied very low voltages and still exhibit a high rate of operation along with reduced harmonic distortion of the output signal, even with input signals of peak-to-peak amplitude above 600 mV.