| 摘要 |
<p>1. Circuit arrangement for the formation of a loop closure in an intermediate regenerator of a PCM system with a first (REG1) and a second (REG2) PCM regenerator, which operate in different directions of transmission, wherein each regenerator includes an input-end equalizer (E1, E2) and, connected thereto, the series arrangement of an amplitude decision device (AE1; AE2), a time decision device (ZE1, ZE2), and a pulse amplifier (V1, V2), and wherein the two regenerators (REG1, REG2) which are on different potential are connected to one another by at least one high-voltage-resistant signal junction (~U2), and moreover the receiving regenerator (REG1) includes a locating-signal analysis arrangement (OSA) which is connected to its amplitude-or time-decision device, and a connected device (SBG, SBE) which serves to control a loop switch (S) for connecting an output of the receiving regenerator (REG1) to an input of a regenerator (REG2) for the opposite direction, wherein a high-voltage transformer (~U1) transmits the control signal for the loop switch (S) to a control frequency receiver (SBE) included in the second regenerator (REG2), wherein the output of the control frequency receiver (SBE) is connected to a control input of the loop switch (S) whose input is connected to an output of the first regenerator and whose output is connected to an input of the second regenerator, characterised in that the output of the locating-signal analysis device (OSA) is connected to the input of a control frequency oscillator (SBG) whose oscillating frequency is approximately 1% of the Nyquist frequency of the PCM signals which are to be transmitted, and that the control frequency oscillator (SBG) includes - as frequency-determining element - the primary winding of the high-voltage transformer (~U1), that the control oscillator (SBG) includes an AND gate (G) which is connected to its control input and whose output is connected via a first resistor (R1) to the collector terminal of a first transistor (T1) and to the first terminal of the primary winding (L1) of the first transformer (~U1), that the second terminal of this primary winding (L1) is connected to the base terminal of the first transistor (T1) and is connected to earth via a first capacitor (C1), that the emitter terminal of the first transistor (T1) is connected directly to earth whereas the collector terminal of this transistor is connected via a second capacitor (C2) to earth, and that the secondary winding (L2) of the first transformer (~U1) is connected to the input of the control frequency receiver (SBE).</p> |
