| 摘要 |
<p>An improved method and circuitry for processing high-impedance (current mode) input signals (20 and 22) for use in translinear and other mode circuits in a manner that avoids the signal dependant bandwidth variations that occur in the prior art. A non-linear feedback structure (36) using a transconductance gain element (46) is employed to extend the bandwidth and/or suppress bandwidth variations encountered in the prior art. One application of this invention is the extension of Gilbert amplifier topologies, with their attendant normalization and integrated circuit implementation advantages, for operation with very low input signal levels (20 and 22) to high bandwidth applications. A further extension in this invention allows this transconductance (46) to be electrically adjusted to allow active bandwidth control or to compensate for signal sources with different input capacitances. The invention is particularly suitable for use as a preamplifier for pairs of sensed photodetector current signals (64 and 66).</p> |
