| 摘要 |
PURPOSE:To halve the number of sampling pulses constituting one call by providing multiple channels separately for transmission and reception and separating transmission and reception of PAM signals between subscriber side and call controlling section. CONSTITUTION:Modulation demodulation circuts MDM1-MDMn of subscribers are connected with modulation democulation circuits MDMS1-MDMSn of a call controlling section through respective multiple channels LT, LR of transmission and reception. MDM1-MDMn are connected with a memory circuit through a decoder 7, and MDMS1-MDMSn are connected with a memory circuit RAM-R through a decoder 8. Clock from a clock generator 4 becomes address input of RAM-T, RAM-R from a clock counter CK. COUNT3 through tristate buffers TSB-1, TSB-2. Consequently, modulation demodulation circuits of subscribers and call controlling section can be controlled by one sampling pulse and the number of sampling pulses of one call can be restricted to two. |
