| Number | Name | Date | Kind |
|---|---|---|---|
| 3183005 | Rockola | May 1965 | |
| 4633452 | Shimbo et al. | Dec 1986 | |
| 4635150 | Kato et al. | Jan 1987 | |
| 4695990 | Kawakami | Sep 1987 | |
| 4750160 | Miller et al. | Jun 1988 | |
| 5022020 | Langman et al. | Jun 1991 | |
| 5105414 | Funabashi et al. | Apr 1992 |
| Number | Date | Country |
|---|---|---|
| 169597 | Jan 1986 | EPX |
| 357814 | Mar 1990 | EPX |
| 2610755 | Feb 1987 | FRX |
| 8601631 | Mar 1990 | WOX |
| 2118758 | Nov 1983 | GBX |
| Entry |
|---|
| Arnolds, Friedrick: "Elektronische MeBtechnik", 1. Auflage, Verlag, Berliner Union, 1976, pp. 269-271. |