SE9303389D0 - Methods to improve receiver sensitivity and speech immunity in DTMF reception (2) - Google Patents

Methods to improve receiver sensitivity and speech immunity in DTMF reception (2)

Info

Publication number
SE9303389D0
SE9303389D0 SE9303389A SE9303389A SE9303389D0 SE 9303389 D0 SE9303389 D0 SE 9303389D0 SE 9303389 A SE9303389 A SE 9303389A SE 9303389 A SE9303389 A SE 9303389A SE 9303389 D0 SE9303389 D0 SE 9303389D0
Authority
SE
Sweden
Prior art keywords
signal
dtmf
methods
difference
receiver sensitivity
Prior art date
Application number
SE9303389A
Other languages
Swedish (sv)
Other versions
SE500918C2 (en
SE9303389L (en
Inventor
Slaven Zimbrek
Original Assignee
Ericsson Telefon Ab L M
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ericsson Telefon Ab L M filed Critical Ericsson Telefon Ab L M
Priority to SE9303389A priority Critical patent/SE500918C2/en
Publication of SE9303389D0 publication Critical patent/SE9303389D0/en
Publication of SE9303389L publication Critical patent/SE9303389L/en
Publication of SE500918C2 publication Critical patent/SE500918C2/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/46—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Noise Elimination (AREA)

Abstract

The number of zero-crossings in each band of a dual-tone multifrequency (DTMF) signal is counted and compared with that in immediately preceding measurement periods. The magnitude of any difference is established and when it is at least equal to a threshold value, pref. one, the input signal is considered to be a DTMF signal. - The energy parameter, representative of the tone energy in a signal, is measured in real time in each band, and three threshold values for the difference from average values determined. The measured difference values are compared with the thresholds to determine if a DTMF signal exists. An interference frequency is accepted when occurring in successive measuring periods.
SE9303389A 1993-10-14 1993-10-14 Improving sensitivity and speech immunity in multifrequency receiver - counting and processing in real time input signal zero-crossings, in lower and higher frequency bands of dual-tone multifrequency signals SE500918C2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SE9303389A SE500918C2 (en) 1993-10-14 1993-10-14 Improving sensitivity and speech immunity in multifrequency receiver - counting and processing in real time input signal zero-crossings, in lower and higher frequency bands of dual-tone multifrequency signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9303389A SE500918C2 (en) 1993-10-14 1993-10-14 Improving sensitivity and speech immunity in multifrequency receiver - counting and processing in real time input signal zero-crossings, in lower and higher frequency bands of dual-tone multifrequency signals

Publications (3)

Publication Number Publication Date
SE9303389D0 true SE9303389D0 (en) 1993-10-14
SE9303389L SE9303389L (en) 1994-01-04
SE500918C2 SE500918C2 (en) 1994-10-03

Family

ID=20391433

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9303389A SE500918C2 (en) 1993-10-14 1993-10-14 Improving sensitivity and speech immunity in multifrequency receiver - counting and processing in real time input signal zero-crossings, in lower and higher frequency bands of dual-tone multifrequency signals

Country Status (1)

Country Link
SE (1) SE500918C2 (en)

Also Published As

Publication number Publication date
SE500918C2 (en) 1994-10-03
SE9303389L (en) 1994-01-04

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Legal Events

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NUG Patent has lapsed