Zero if radio receiver for intermittent operation

• US 5,263,194 A
• Filed: 03/07/1990
• Issued: 11/16/1993
• Est. Priority Date: 03/07/1990
• Status: Expired due to Term

• Current Assignee: Protocol-ip.com, LLC, Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Corporation (Seiko Group), Seiko Epson Corporation (Seiko Group)
• Inventors: Ragan, Lawrence H.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Urban, Edward
• Application Number:
  US07/489,579
• Time in Patent Office: 1,350 Days
• Field of Search: 455/207-209, 455/214, 455/258, 455/264, 455/316-319, 455/324, 455/344, 455/234, 340/825.44
• US Class Current: 455/316
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A radio receiver for use with a time slot paging system which receives intermittent data includes a direct coupled zero IF receiver circuit with at least one automatic gain control (AGC) amplifier stage. DC offset errors are removed from the AGC amplifier stages by a timed zero adjustment circuit that is switched into the AGC circuit just prior to the receipt of data. The resulting zero IF circuit may be miniaturized in monolithic form making it ideal for use in a wristwatch sized pager.

Claims

1. A zero IF receiver for processing radio signals that are modulated on a carrier signal comprising:

(a) RF means for receiving the radio signals;

(b) zero IF down conversion means for converting said radio signals to near zero IF signals;

(c) direct coupled amplifier means coupled to said zero IF down conversion means for providing gain to said near zero IF signal; and

(d) zero adjustment means coupled to said amplifier means for removing DC voltage offsets;

said direct coupled amplifier means comprising a plurality of amplifier stages and further including switching means for sequentially coupling said zero adjustment means to each of said amplifier stages in turn.

2. The zero IF amplifier of claim 11 wherein said switching means couples said zero adjust means to each of said amplifiers in a predetermined sequence, said sequence starting with an amplifier stage coupled to said zero IF down conversion means and proceeding through each stage to a final stage.