Number | Date | Country | Kind |
---|---|---|---|
3934769 | Oct 1989 | DEX |
Number | Name | Date | Kind |
---|---|---|---|
4052562 | Andersen | Oct 1977 | |
4087636 | Akiyama et al. | May 1978 | |
4581758 | Coker et al. | Mar 1986 | |
5048082 | Krafft | Oct 1991 |
Entry |
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German Publication: Elektronik, 22, Oct. 30, 1987, p. 87ff; Chandra Desai, "Frei sprechen ohne Ruckkopplung". |