Spread spectrum chip rate tracking system
US5841808A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 1995 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Mar 23, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7085
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a new receiver design, the specific transmitter unit is unchanged from a prior patent application but may also be substantially as described in the prior art. The transmitter is initially activated by the input of the pseudo-random generator code. This code may be any alpha-numeric series, but must be identical to that input to the receiver. When the code is input through the keypad, the transmitter uses internal algorithms to generate a unique shift-register feedback combination. This creates a pseudo-random (PN) code which repeats after a programmable number of bits, depending upon desired maximal signal correlation time. That is the longer the code the longer the correlation time. This PN code sequence is clocked at the desired clock (CHIP) rate inside the transmitter unit. The PN code sequence which is thus generated is then added in phase to the data which is a substantially lower rate than the CHIP rate. After mixing with the PN code and data, the RF frequency CW signal power is spread across a frequency band equivalent to twice the PN code clock rate. The signal power density per hertz is now well below an identical non-spread signal at the communications data rate and id…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.