IMPROVED AMPLIFYING CIRCUIT

• US 3,671,884 A
• Filed: 09/29/1970
• Issued: 06/20/1972
• Est. Priority Date: 09/29/1970
• Status: Expired due to Term

• Current Assignee: John H. Denny Jr
• Original Assignee: John H. Denny Jr
• Inventors: John, H. Denny Jr.
• Primary Examiner(s): Alfred L. Brody
• Application Number:
  US05/076,529
• Time in Patent Office: 630 Days
• Field of Search: 332/16T,16,18,19,29 307/249 330/10 325/318 329/101,103
• US Class Current: 330/302
• CPC Class Codes: H03F 1/48 of aperiodic amplifiers
• CPC Class Codes: H03F 2200/198 A hybrid coupler being used as coupling circuit between stages of an amplifier circuit
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602

Abstract

Radiofrequency signals and lower frequency signals are separately amplified without mixing in a single transistor by applying the lower frequency signals through a filter to the transistor base and deriving the amplified lower frequency signals in an emitter-follower circuit, and by applying the radiofrequency signals to the transistor emitter and deriving the amplified radiofrequency signals from the transistor collector with the transistor base being connected in a common base configuration.

Claims

1. An improved circuit for separately amplifying radio frequency signals and lower frequency signals comprising:

a. a transistor having an emitter, a base, and a collector;

b. first and second terminals for supplying direct current power;

c. a resistor bias circuit connected between said first and second terminals;

d. means connecting a selected point on said bias circuit to said transistor base;

e. a bias and lower frequency output resistor connected between a point on said bias circuit and said transistor emitter;

f. a filter circuit having an input for receiving lower frequency signals for amplification and having an output;

g. said filter circuit including means for passing said lower frequency signals and for blocking direct current and said radiofrequency signals;

h. means connecting said filter circuit output to said transistor base;

i. a capacitor connected to said transistor emitter for supplying radio frequency signals to be amplified, and for deriving amplified lower frequency signals;

j. means connected to said transistor collector for deriving amplified radio frequency signals therefrom;

k. and means connected between said transistor collector and one of said terminals for supplying direct current power to said transistor.

2. The improved circuit of claim 1 wherein said filter circuit comprises an inductor and a capacitor connected in series between said filter circuit input and output, and comprises a shunt capacitor connected between said series circuit and one of said terminals.