PT77303A - Apparatus for identifying digital multi-frequency signals - Google Patents
Apparatus for identifying digital multi-frequency signalsInfo
- 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
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.
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) |
-
1983
- 1983-09-08 PT PT7730383A patent/PT77303B/en unknown
Also Published As
Publication number | Publication date |
---|---|
PT77303B (en) | 1986-03-20 |
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