NOISE CANCELLATION FILTER SYSTEM

• US 3,605,012 A
• Filed: 07/15/1969
• Issued: 09/14/1971
• Est. Priority Date: 07/15/1969
• Status: Expired due to Term

• Current Assignee: Jacob H. Kubanoff
• Original Assignee: Jacob H. Kubanoff
• Inventors: Kubanoff, Jacob H.
• Primary Examiner(s): Smith, Alfred E.
• Application Number:
  US04/841,825
• Time in Patent Office: 791 Days
• Field of Search: 324/78F 328/165 325/473,475,476
• US Class Current: 324/76.68
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H

Abstract

There is provided a system which detects a desired signal in the presence of random noise. A plurality of filters having successively adjacent passbands simultaneously receive a composite of noise and desired signal. Each filter passes only that portion of the composite within its respective passband. All portions are then integrated and thereafter alternate portions are inverted. Inverted and noninverted portions are then summed, the desired signal, if present, appearing as a residue. Sensing indicators connected to each summer output then indicate within which filter the desired signal appeared.

Claims

1. A noise cancellation circuit for separating the intelligence portion from the noise of a transmission within a frequency spectrum which circuit comprises:

a plurality of channels, each channel having connected therein;

a first band-pass filter for passing only therethrough a first narrow frequency band, a second band-pass filter for passing only therethrough a second narrow frequency band equal in bandwidth to and frequency contiguous said first narrow frequency band and having a common boundary therewith, wherein each of said channels encompasses a different region of said frequency spectrum, a pair of identical integrators, an inverter, a summing means having a pair of inputs and one output for providing an output signal which is the sum of the input signals, a first circuit path having connected in series therein said first band-pass filter, one of said integrators and one input of said summing means, a second circuit path having connected in series therein said second band-pass filter, the other of said integrators, said inverter, and the other input of said summing means, whereby, when said transmission is applied simultaneously to the inputs of said filters the output of said summing means will be only said intelligence portion.

2. The noise cancellation circuit according to claim 1 further incLuding an OR gate having a plurality of inputs each connected to receive the output of one of said summing means.

3. The noise cancellation circuit according to claim 2 further including for each channel:

a pair of visual signal indicators connected to receive the output of said summing means, a pair of diodes each connected intermediate said summing means and one of said indicators but of a polarity orientation whereby current will flow only in one direction to one of said indicators and in the opposite direction to the other of said indicators.