| 摘要 |
919,167. Pulse multiplex switching systems. TELEFONAKTIEBOLAGET L. M. ERICSSON. June 16, 1959 [June 18, 1958], No. 20651/59. Class 40 (4). [Also in Group XL (b)] In a switching system in which signals are interchanged over a multiplex highway, between storage devices associated with signal sources via low-pass filters, the filters comprise a substantially (though not exactly) symmetrical pinetwork preceded by a series-connected parallelresonant circuit. As shown, signals from a source R are applied via a repeatedly pulsed switch K to a pulse highway for energy transfer to other such circuits (denoted symbolically by Z), interchange of energy taking place between delay circuits DL having a delay equal to half the pulse duration. The resonance frequency of the series circuit L 1 C 1 should lie between 0.5 and 0.55 times the pulse repetition frequency. The resonance frequency of the pi-network C 2 L 2 C 3 should be less than half and preferably about 0.4 times the pulse repetition frequency. The Specification shows that such a circuit gives an improved pass band characteristic and is also effective to attenuate lower side bands of the pulse repetition frequency. Specification 737,417 is referred to. |
