Processes for generating duo-binary FSK, tamed FSK and TFM modulations and modulators applying those processes
US4426710A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Sep 17, 1981 |
| Grant date | Jan 17, 1984 |
| Priority date | — |
| Expiry date | Sep 17, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2007
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
To obtain a duo-binary FSK modulation, the modulating binary signal train has a three state partial response and is fed through a precoding, a transition-type coding, a simplified MSK modulation at the carrier frequency, a frequency division by two, and a multiplication by the same signal delayed by one binary element period. In order to obtain a "tamed FSK" modulation, the modulating binary signal train has a five state partial response and is fed through precoding, a transition-type coding, a simplified MSK modulation at the carrier frequency, a frequency division by two, a multiplication by the same signal delayed, for one part, by one binary element period and, for the other part, by two binary element periods. A TFM modulation is obtained by using the FSK duo-binary generating process, but a wave shaping filter is connected between the division by two circuit and the multiplication circuit. In a TFM modulator, the train of binary signals is applied to a partial response precoding circuit, the output of which is connected to a transition-type coding circuit, the output of which is connected to the input of a simplified MSK modulator, the output of which is connected to the inpu…
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