Differential amplifier having independently tunable base gain, peak gain and boost frequency, and uses of same
First Claim
1. A differential amplifier comprising:
- (a) first and second transistors having respective first and second drain nodes through which sum-constant currents respectively flow; and
(b) first and second variable drain impedances respectively coupled to the first and second drain nodes, each of the variable drain impedances having an inductance (L), a capacitance (C) and a resistance (R), wherein at least said resistance (R) of each of the first and second variable drain impedances is adjustable and wherein at least one of said L and C of each of the first and second variable drain impedances is independently adjustable so that an output voltage versus the input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency which is greater than a base gain of the differential amplifier at 0 Hz and so that the peak gain and base gain can be adjusted independently of one another.
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Accused Products
Abstract
A waveform shaping method comprises: (a) receiving link-distorted signal pulses; (b) passing the link-distorted signal pulses through a series of differential amplifiers each have independently tunable, base gains, peak boost gains, boost frequencies and boost bandwidths; and (c) adjusting one or more of the base gains, peak boost gains, boost frequencies and boost bandwidths of the series of differential amplifiers so as to realize a selective and progressive waveform re-shaping of the link-distorted signal pulses. In one embodiment, each amplifier in the series has first and second transistors with respective first and second drain nodes through which sum-constant currents respectively flow; and first and second, variable drain impedances (Zd1, Zd2) coupled to the first and second drain nodes, where each of the variable drain impedances has a non-negligible inductance (L), a non-negligible capacitance (C) and a non-negligible resistance (R), and where at least two of the R, L and C factors are programmably and independently adjustable so that an input voltage versus output voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency which is greater than a base gain of the differential amplifier at 0 Hz.
28 Citations
28 Claims
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1. A differential amplifier comprising:
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(a) first and second transistors having respective first and second drain nodes through which sum-constant currents respectively flow; and (b) first and second variable drain impedances respectively coupled to the first and second drain nodes, each of the variable drain impedances having an inductance (L), a capacitance (C) and a resistance (R), wherein at least said resistance (R) of each of the first and second variable drain impedances is adjustable and wherein at least one of said L and C of each of the first and second variable drain impedances is independently adjustable so that an output voltage versus the input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency which is greater than a base gain of the differential amplifier at 0 Hz and so that the peak gain and base gain can be adjusted independently of one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A differential amplifier comprising:
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(a) first and second transistors having respective first and second drains through which first and second drain currents respectively flow; and (b) first and second variable drain impedances respectively coupled to the first and second drains, each of the variable drain impedances having an inductance (L), a capacitance (C) and a resistance (R), wherein at least one of said R, L and C is adjustable so that an output voltage versus input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency which is greater than a base gain of the differential amplifier at 0 Hz;
wherein;(b.1) at least said inductance (L) of each of the first and second variable drain impedances is adjustable and the differential amplifier includes inductance-selecting switches having capacitances that are resistively separated from the capacitances (C) of the first and second variable drain impedances.
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16. A differential amplifier that exhibits an output voltage versus input voltage transfer function having a peak gain at a corresponding peak boost frequency which is greater than a base gain of the differential amplifier at 0 Hz, said differential amplifier comprising:
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(a) first and second opposed active devices; and (b) respective first and second reactive loads, operatively coupled respectively to the first and second active devices, each of the first and second reactive loads including a variable resistance and at least one of a variable inductance and a variable capacitance, said variable resistance being adjustable independently of the at least one variable inductance and variable capacitance so that the base gain of the amplifier can be adjusted independently of said peak gain. - View Dependent Claims (17, 18)
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19. A reconfigurable differential amplifier comprising:
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(a) a first transistor having a first drain through which a respective first drain current flows; (b) a second transistor having a second drain through which a respective second drain current flows, where the first and second transistors are matched and a sum of the first and second drain currents remains substantially constant during a given configuration of the reconfigurable differential amplifier; (c) a first variable drain impedance coupled to the first drain, the first variable drain impedance having a respective first inductance (L1), first capacitance (C1) and first resistance (R1), wherein at least one of said R1, L1 and C1 is variable; (d) a second variable drain impedance coupled to the second drain, the second variable drain impedance having a respective second inductance (L2), second capacitance (C2) and second resistance (R2), wherein at least one of said R2, L2 and C2 is variable and the second variable drain impedance is matched to the first variable drain impedance; wherein said first and second variable drain impedances are configurable so that an output voltage versus input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency and where the peak gain is greater than a base gain of the differential amplifier at 0 Hz; and (e) base gain adjusting means responsive to a variable control signal supplied from an adaptive controller for varying said base gain, where the control signal changes in adaptive response to changing stimuli supplied to the adaptive controller. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A reconfigurable differential amplifier comprising:
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(a) a first transistor having a first drain through which a respective first drain current flows; (b) a second transistor having a second drain through which a respective second drain current flows, where the first and second transistors are matched and a sum of the first and second drain currents remains substantially constant during a given configuration of the reconfigurable differential amplifier; (c) a first variable drain impedance coupled to the first drain, the first variable drain impedance having a respective first inductance (L1), first capacitance (C1) and first resistance (R1), wherein at least one of said R1, L1 and C1 is variable; (d) a second variable drain impedance coupled to the second drain, the second variable drain impedance having a respective second inductance (L2), second capacitance (C2) and second resistance (R2), wherein at least one of said R2, L2 and C2 is variable and the second variable drain impedance is matched to the first variable drain impedance; wherein said first and second variable drain impedances are configurable so that an output voltage versus input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency and where the peak gain is greater than a base gain of the differential amplifier at 0 Hz; wherein the base gain is adjustable; and
wherein;(b.1) at least the respective first and second resistances (R1, R2) of the first and second variable drain impedances are adjustable. - View Dependent Claims (26)
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27. A reconfigurable differential amplifier comprising:
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(a) a first transistor having a first drain through which a respective first drain current flows; (b) a second transistor having a second drain through which a respective second drain current flows, where the first and second transistors are matched and a sum of the first and second drain currents remains substantially constant during a given configuration of the reconfigurable differential amplifier; (c) a first variable drain impedance coupled to the first drain, the first variable drain impedance having a respective first inductance (L1), first capacitance (C1) and first resistance (R1), wherein at least one of said R1, L1 and C1 is variable; (d) a second variable drain impedance coupled to the second drain, the second variable drain impedance having a respective second inductance (L2), second capacitance (C2) and second resistance (R2), wherein at least one of said R2, L2 and C2 is variable and the second variable drain impedance is matched to the first variable drain impedance; wherein said first and second variable drain impedances are configurable so that an output voltage versus input voltage transfer function of the differential amplifier can exhibit a peak gain at a corresponding peak boost frequency and where the peak gain is greater than a base gain of the differential amplifier at 0 Hz; and (e) variable transconductance means which is adjustable independently of adjustable ones of said R1 R2, L1 and L2, and C1 and C2, the variable transconductance means being for providing the differential amplifier with a variable transconductance factor (gm).
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28. A reconfigurable differential amplifier comprising:
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(a) a first transistor having a first drain through which a respective first drain current flows; (b) a second transistor having a second drain through which a respective second drain current flows, where the first and second transistors are matched and a sum of the first and second drain currents remains substantially constant during a given configuration of the reconfigurable differential amplifier; (c) a first variable drain impedance coupled to the first drain, the first variable drain impedance having a respective first inductance (L1), first capacitance (C1) and first resistance (R1), wherein R1 is variable and at least one of L1 and C1 is variable independently of R1; (d) a second variable drain impedance coupled to the second drain, the second variable drain impedance having a respective second inductance (L2), second capacitance (C2) and second resistance (R2), wherein R2 is variable and at least one of L2 and C2 is variable independently of R2.
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Specification