Multifrequency digital signal receiver
US4223185A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1978 |
| Grant date | Sep 16, 1980 |
| Priority date | — |
| Expiry date | Nov 14, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/4575
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A multifrequency code receiver for signals consisting of the sampled and encoded sum of q sinusoids of amplitudes A.sub.f, whose frequencies f are regularly spaced apart by .DELTA.F.sub.i =p.DELTA.F.sub.O (.DELTA.F.sub.O being a divisor of the sampling frequency F.sub.E) the receiver possessing a heterodyne device transforming each value f into F.sub.L -f, a multiple of .DELTA.F.sub.O, a counter counting up to r, where r=F.sub.E /F.sub.T, F.sub.T being the divisor of F.sub.E greater than (q-1).DELTA.F.sub.i, filtering circuit, a fast Fourier transform (FFT) computer for N.sub.T =F.sub.T /.DELTA.F.sub.O samples producing the amplitudes A.sub.f.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.