US 4,232,272 AGranted

Feedback-stabilized multistage frequency-selective amplifier

AssigneeCSELT - Centro Studi e Laboratori Telecomunicazioni S.p.A.

InventorBruno Fabri

Life of this patent

Estimating the term…

Loading patent…

Abstract

An amplifier having a high gain in a selected frequency band, e.g. for the preferential amplification of a pilot oscillation, consists of a plurality of cascaded stages each comprising an active component, a coupling network and a negative-feedback network. The coupling and feedback networks are alternately connected in a series circuit between a signal input and a signal output, each of these networks (with the possible exception of those associated with the first stage) comprising a damped parallel-resonant circuit with an inductive branch forming a low-ohmic path for direct current. Each active component has an input electrode connected through a stabilizing resistor to the junction of the associated coupling and feedback networks, its output electrode being tied to the downstream end of the corresponding feedback network. Operating current is supplied to the active component of the last stages through a choke connected directly to its output electrode, the output electrodes of the preceding stage receiving such operating current from the choke via some of the series-connected networks.

Claims6

Dependent claims

A feedback-stabilized frequency-selective amplifier comprising:

a plurality of cascaded amplification stages each including an active component with an input electrode, an output electrode and a common electrode;
a plurality of coupling networks and a like plurality of feedback networks alternately inserted in a series chain between a signal-input terminal and a signal-output terminal, said input electrode of each active component being connected to a junction of a coupling network and a partly inductive feedback network of said chain in a network pair respectively associated therewith, said output electrode of each active component being connected to a downstream end of the associated feedback network;
and
a supply of direct current connected between the common electrodes of all active components and a downstream end of said chain proximal to said signal-output terminal for feeding operating power to said stages, said coupling networks having lower impedances than the associated feedback networks for signal frequencies lying within a predetermined band, at least the coupling and feedback networks downstream of the first of said stages having inductive branches conductively interconnected at their junctions with formation of a continuous low-resistance path for direct current from said supply to the output electrodes of all active components.

1 more element

Dependencies are inferred from the claim text.