Infrared receiving unit

• US 8,886,146 B2
• Filed: 10/08/2009
• Issued: 11/11/2014
• Est. Priority Date: 10/13/2008
• Status: Active Grant

• Current Assignee: Sennheiser Consumer Audio GmbH (Sonova Holding AG)
• Original Assignee: Sennheiser Electronic GmbH & Company KG
• Inventors: Andres, Joerg, Reymann, Dirk
• Primary Examiner(s): Aminzay, Shaima Q
• Application Number:
  US13/123,764
• Publication Number:
  US 20110255880A1
• Time in Patent Office: 1,860 Days
• Field of Search: 455/226.1, 455/522, 455/212, 455/218, 455/220, 455/222, 455/223, 455/226.2, 455/70, 375/217, 375/227, 375/242, 379/6.3, 379/201.06, 379/202, 348/553, 348/33
• US Class Current: 455/226.1
• CPC Class Codes: H03G 3/341 Muting when no signals or only weak signals are present H03G3/344, H03G3/345 take precedence
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal

Abstract

An IR receiver having a decision logic circuit for activating or deactivating a squelch. Activation or deactivation of the squelch is effected in dependence on a mean value of the frequency, a variance of the receiver intermediate frequency, a mean value of the audio amplitude, a variance of the audio amplitude and/or a signal strength of the receiver intermediate circuit frequency.

Claims

1. An infrared receiver comprising:

a decision logic circuit configured to activate or deactivate a squelch and to determine whether a meaningful signal is present;

a demodulator adapted to demodulate a received intermediate frequency;

a high-pass filter adapted to perform a high-pass filtering of an output of the demodulator; and

a rectifier for rectifying an output signal of the high-pass filter;

wherein the squelch is deactivated when a meaningful signal is determined;

wherein the decision logic circuit is configured to determine whether a signal strength of a received receiver intermediate circuit frequency signal is below a predetermined threshold, and to determine in this case that the signal is not a meaningful signal;

wherein the decision logic circuit is configured to determine whether a variance of a carrier frequency of the received receiver intermediate frequency signal is above a predetermined threshold value, and to determine that this signal is not a meaningful signal in this case;

wherein the decision logic circuit is configured to determine whether a mean value of an audio amplitude is above a predetermined threshold, and to determine that the signal is not a meaningful signal in this case; and

wherein an output signal of the rectifier corresponds to the mean value of the audio amplitude.

2. The infrared receiver as set forth in claim 1;

wherein the decision logic circuit is configured to determine whether the variance of the audio amplitude of the receiver intermediate circuit frequency signal is greater than a predetermined threshold, and to determine that this signal is not a meaningful signal in this case.

3. The infrared receiver as set forth in claim 1;

wherein the decision logic circuit is configured to store the mean value of the carrier frequency of the received signal in a memory when the variance of the carrier frequency is below a predetermined threshold value.

4. The infrared receiver as set forth in claim 3;

wherein the decision logic circuit is configured to determine whether the carrier frequency is sufficiently close to a stored frequency, and to determine that the signal is a meaningful signal in this case.

5. An infrared receiver comprising:

a decision logic circuit which is configured to determine whether a received signal represents a meaningful signal based on an evaluation of a variance of a frequency, a mean value of an audio amplitude, and a signal strength of a receiver intermediate frequency signal;

a demodulator adapted to demodulate a received intermediate frequency;

a high-pass filter adapted to perform a high-pass filtering of an output of the demodulator; and

a rectifier for rectifying an output signal of the high-pass filter;

wherein an output signal of the rectifier corresponds to the mean value of the audio amplitude.

6. A method of activating or deactivating a squelch in an infrared receiver, the method comprising:

deactivating the squelch when the signal is determined as a meaningful signal;

determining whether a signal strength of a received receiver intermediate frequency signal is below a predetermined threshold value, and determining in this case that the signal is not a meaningful signal;

determining whether a variance of a carrier frequency of the received receiver intermediate frequency signal is above a predetermined threshold, and determining in this case that the signal is not a meaningful signal; and

determining whether a mean audio signal amplitude is above a predetermined threshold value, and determining in this case that the signal is not a meaningful signal;

demodulating a received intermediate frequency to obtain a demodulated output;

high-pass filtering the demodulated output to obtain a high-pass-filtered output signal; and

rectifying the high-pass output signal to obtain a rectified output signal;

wherein the rectified output signal corresponds to the mean audio signal amplitude.