Patent GB-820864-A (GB)
Title: Improved dial impulse register
Inventor: KIYASU ZENICHI
IPC: G11C11/20
Filed: 1956-05-31
Abstract: 820,864. Automatic exchange systems. NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION. May 31, 1956, No. 16915/56. Classes 40 (4) and 40 (9). [Also in Group XIX] In an exchange system, parametricallyexcited oscillators, described as parametrons, are used in a digit register. In a typical parametron, Fig. 1a, a tuned circuit L, C oscillates at frequency f (which may be of the order of 1 Mc/s.) when the magnetic cores M are excited at frequency 2f, the cores being wound to avoid transformer action. The circuit oscillates in one of two phases denoted 0, 1 differing by #. The phase is established by a control oscillation momentarily applied to terminal 3. A parametron may have three input terminals 3, 4, 5, Fig. 1c, and one output terminal 6, the control currents being confined to the phases 0, 1. In an AND element, one terminal 3 is always excited in phase 0 and the output is in phase 1 only when both the control terminals 4, 5 are in phase 1. In an OR element one terminal 3 is always in phase 1 and the output is in phase 1 when either (or both) terminals 4, 5 is in phase 1. Symbols for AND and OR elements are shown in Figs. 2b, 2c. Each parametron is excited periodically in one of three cyclic periods I, II, III. The exciting periods of the three cycles overlap as shown in Fig. 2g so that the output of a I-period parametron may control a II-period parametron and so on. The operation progresses in the order I-II, II-III, III-I. Receiving impulses. Figs. 3a, 3b.-A parametron 7 is linked to parametron 9, a lattice network comprising direct connections 1, 3 and 2, 4 through coils L1, L<1>1 and cross-connections 1, 4 and 2, 3 through coils L2, L<1>2. The impedance of the saturable core on which coils L1, L<1>1 are wound is controlled by the line current in Id. With the phase fixed in parametron 7 the condition of 9 is reversed at each make or break in the line circuit. In Fig. 3b, parametron P1 is coupled to parametron P2 through two oppositely-wound primary coils on a transformer T. When the line is open, P1 is coupled to P2 only through resistor R2. When the line is closed, rectifier 9 conducts and the control signal from P1 to P2 is reversed in phase, the signal transmitted through P1 being greater than that transmitted through R2. Generation of timing pulses. Fig. 4.-Three parametrons 11, 12, 13 operate cyclically in a loop, the period of the cycle being 0.5 millisecs. Each parametron is excited for 0.025 millisecs. in each cycle. Eight loops 14 to 16, 18 to 20, . . . 42 to 44 all cycle normally in phase 0 and form a counter A. Parametron 11 given phase 1 and phase 0 signals alternately. For every two 1 signals from 11, parametron 17 gives a phase 1 signal. Similarly, parametrons 21, 25 and 45 give one signal for every 4, 8 and 256 signals from 13. A timing signal of 0.025 millisecs. is applied by 45 to lead 9 once in 12.8 millisecs. Detection of interdigital pause.-Parametron 9, Fig. 4, applies phase 1 to lead b when the line Id is looped and phase 0 when the loop is broken. A counter B, Fig. 5 (like counter A, Fig. 4) is stepped by timing pulses on lead c but is reset by each make or break signalled on lead b. The first timing pulse on c changes parametron 106 to phase 1, 107 follows and the loop 103, 104, 105 cycles in phase 1. Subsequent timing pulses do not produce a phase 1 signal from 107 in view of the NOT input from 103. When lead b signals phase 0 at the beginning of an impulse, parametrons 107, 102 are both set to phase 1 and the loop 103, 104, 105 cycles in phase 0 in view of the NOT input to 105. Thus, parametrons 107, 102 give phase 1 signals at make-and-break respectively. These signals are repeated as phase 0 signals by parametrons 108, 109, 110 to reset counter B. If the interval between two signals from 108, 109, 110 is long enough (8 Î 12.8 millisecs.), parametron 123 injects phase 1 into the loop 124, 125, 126, counting is stopped by the NOT signal applied to 111 and the end of a digit is signalled to parametrons 127, 128 providing that 103 still indicates that the line is looped. Impulse counter.-The 1 signals from parametron 102 are counted by a counter C, Fig. 6, which transmits them as 2 in 5 code signals to parametrons 149-153. The counter is like B in Fig. 5 but has four loops and two extra elements 147, 148. Parametron 147 becomes phase 1 when two of the last three loops are phase 1. Parametron 148 becomes phase 1 when one or none of the four loops is phase 1. Parametrons 154-159 reset the counter C after a short delay when 127 signals the end of the digit. Digit counter, Fig. 7.-The three code digits and the four numerical digits of a called number are counted by means of three loops 162-164, 166-168, 170-172 and auxiliary elements 173, 178, 189, &c. Parametrons 182-188 give phase 1 signals in turn as the seven digits are counted. The counter is reset by means of parametrons 179-181 and connections R7, R8, R9 when the marker signals over lead u that the connection is made or that dialling has been left incomplete. Register, Fig. 8.-The register for the seven digits comprises a matrix of 35 ferrite cores M11-M75 of 2 mm. diameter. Two horizontal rows of cores are linked with the parametrons 149-153 controlled by the impulse counter C of Fig. 6. Seven vertical columns of cores are linked with the parametrons 201-207. The parametrons 201-207 are operated in turn by the parametrons 182-188 of the digit counter. If the output of parametrons 182-188, of frequency f, is used to excite 201 to 207, the frequency applied to the cores is only f/2. The frequency applied to the cores from parametrons 149-153, however, is f. If the phase of f/2 is fixed, a core excited simultaneously by f and f/2 is magnetized to register either 1 or 0 according to the phase of f. When the code of the first digit is displayed on elements 149-153 in combination with 201, the code is registered on cores M11-M15. The information is read out, without destruction when 201 is again excited by the marker over terminal S1 and the code registered on cores M11-M15 is picked up by parametrons 196-200. A bi-quinary count, Fig. 12, comprises seven loops identified by the parametrons 501, 504, 508, 512, 516, 520, 524. All the loops cycle in phase 0 when re-set by a phase 0 signal from 528 which is connected to all the elements marked R7. The signal from 528 returns to 1 phase. The elements R7 then behave as OR elements and the first signal to the upper input terminal sets element 507, 501 to phase 1 and both loops cycle in phase 1. Element 507 returns to phase 0 or the third excitation period. At the next signal element 511 and loop 508 are set in phase 1 and loop 504 returns to phase 0. With loop 501 cycling in phase 1, the first five impulses produce signals in leads 1-5 and at the fifth impulse loop 501 returns to phase 0. At the sixth impulse loops 524 and 504 are both set in phase 1 and signals appear on leads 1 and V. The second five are counted like the first but a signal remains on lead V.