PT77303A - Apparatus for identifying digital multi-frequency signals - Google Patents

Apparatus for identifying digital multi-frequency signals

Info

Publication number
PT77303A
PT77303A PT7730383A PT7730383A PT77303A PT 77303 A PT77303 A PT 77303A PT 7730383 A PT7730383 A PT 7730383A PT 7730383 A PT7730383 A PT 7730383A PT 77303 A PT77303 A PT 77303A
Authority
PT
Portugal
Prior art keywords
receivers
selective
nonselective
receiver
squared
Prior art date
Application number
PT7730383A
Other languages
Portuguese (pt)
Other versions
PT77303B (en
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 PT7730383A priority Critical patent/PT77303B/en
Publication of PT77303A publication Critical patent/PT77303A/en
Publication of PT77303B publication Critical patent/PT77303B/en

Links

Landscapes

  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

The signal passes through a digital gp. filter to six selective receivers and two nonselective receivers. In the selective receivers the input at each sampling instant is multiplied by two coeffts., from separate sets, one formed by weighting of a sine function and the other by similar weighting of another sine function phase-shifted by 90 deg. The two prods. are accumulated, squared and added for a measure of signal energy in the passband. One nonselective receiver responsive to composite input level changes controls the start of calculation in the selective receivers. The other nonselective receiver generates a measure of the envelope amplitude, which is squared and compared with the sum of selective receiver outputs. Threshold logic decides whether a multifrequency digital input is present.
PT7730383A 1983-09-08 1983-09-08 Apparatus for identifying digital multi-frequency signals PT77303B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PT7730383A PT77303B (en) 1983-09-08 1983-09-08 Apparatus for identifying digital multi-frequency signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PT7730383A PT77303B (en) 1983-09-08 1983-09-08 Apparatus for identifying digital multi-frequency signals

Publications (2)

Publication Number Publication Date
PT77303A true PT77303A (en) 1983-10-01
PT77303B PT77303B (en) 1986-03-20

Family

ID=20083363

Family Applications (1)

Application Number Title Priority Date Filing Date
PT7730383A PT77303B (en) 1983-09-08 1983-09-08 Apparatus for identifying digital multi-frequency signals

Country Status (1)

Country Link
PT (1) PT77303B (en)

Also Published As

Publication number Publication date
PT77303B (en) 1986-03-20

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