Patent GB-404514-A (GB)
Title: Method of and means for effecting the automatic regeneration of received wheatstone telegraph signals
IPC: H04L25/42
Filed: 1933-04-19
Abstract: 404,514. Code telegraphy. NIELSEN, T. C. V., 37, Solsortvej, Frederiksberg, Denmark. April 19, 1933, No. 11491. Convention date, July 23, 1932. [Class 40 (iii).] In a method of regeneration of Wheatstone signals separate members are employed for the reception of the positive and negative impulses in such a manner that the members which arc arranged for the reception of the positive impulses can only be actuated during those intervals, of duration equal to that of a signal unit, which follow the instants at which changes from negative to positive are possible in perfect Wheatstone signals, whilst the operation of the members allocated to the reception of negative impulses is similarly related to the changes from positive to negative in such signals. The invention is based on a characteristic of the Morse code that successive changes from positive to negative or from negative to positive are separated by time intervals which are multiples of two units of time-the unit of time being the interval during which current is sent for a dot. In the receiving and repeating system shown in Fig. 4 the impulses following the change from negative to positive and during alternate intervals are applied to a condenser G, whilst the impulses during the unit interval following the change from negative to positive and alternate unit intervals are applied to condenser H. With the transmitting and receiving distributers synchronized and the armature of line relay LR on its positive contact as brush I passes over one of the odd numbered segments of set A, condenser G is charged from a battery 25. When the brush III moves on to the next segment brushes II and III discharge the condenser through a winding 27 of a relay SR which connects positive battery to the line L2. In the unit interval when condenser G is discharging, a segment of ring D co-operates with brushes IV and V to charge the condenser H if the armature 26 of line relay LR has moved to its negative contacts. When the brushes move on to the next segment, brushes V and VI discharge condenser H through the winding 28 which operates armature 29 to send a negative impulse to line or to a perforator. The first impulse of a dash produces the same effect as a dot, but since the .line relay armature 26 remains against the positive contact for three unit intervals, brush IV does not charge condenser H during the second interval of the dash during which condenser G discharges through winding 27 to initiate the transmission of the dash signal over the line L2. During the third interval, G is again charged, and as condenser H was not charged during the previous interval, armature 29 remains on the positive contact for the second element of the dash. Following the change from positive to negative, at the end of the dash condenser G discharges through winding 27, but without effect on the armature 29, whilst brush IV co-operates with a segment of ring D to charge condenser H since the armature 26 is now on the negative contact in response to the first spacing element. During the second uni interval of the spacing current, brushes V and VI cooperate to discharge condenser H through winding 28 bringing the armature 29 to the negative contact for transmitting the first element of the spacing signal. When single current working is employed, e.g. over a wireless channel-the segments of the ring A are cut down to a portion representing a fraction of the unit time interval, whilst the remaining segments remain as before. If an accidental impulse, e.g. an atmospheric occurs, moving armature 26 to the positive contact during a period of no current, i.e., when armature 26 of the receiving relay should be on the negative contact, this extraneous impulse has no effect on the condenser G unless it occurs during the restricted interval when the brush I is passing over the centre (unshaded) part of one of the segments 1, 3, 5 .. of ring A. In a modification, Fig. 9, the condensers G, H are replaced by relays R1, R2 each of which has three windings effecting operation, locking and release. The operating winding 34 of relay R1 is connected to segments 1, 3, 5 .. of ring B2, whilst the releasing winding 35 is connected to segments 2, 4, 6 .. of ring C2 and is in the circuit of the sending relay SR. When the armature 31 of line relay LR is on the positive contact as brush 33 passes over an oddnumbered segment, winding 34 operates the armature 38 to the positive contact, and the relay R1 locks up over winding 36-the current being sufficient to overcome the effect of a negative impulse from the contact of line relay LR if it should occur before brush 33 leaves an odd-numbered segment. When the brush 50 moves to an even-numbered segment of ring C2, current passes from battery 40 through release winding 35 and ring D2 to operate relay SR to the positive contact. The current passing through the release winding 35 is sufficient to overcome the locking current allowing the armature 38 to be restored to its normal position. If the succeeding impulse is of opposite polarity relay R2 operates and releases in a manner similar to that described for R1 and operates armature 53 to the negative contact. When a long positive impulse is received, relay R1 releases after the first unit has been retransmitted but as R2 is not energized, no current is applied to the relay 51 during the second interval and its armature remains against the contact connected to positive battery. Relay R1 will re-energize and lock up during the third unit interval and during the next interval will release after passing current to the relay 51, but without effect. During this interval relay R2 energizes, locks up, and, during the following unit interval when brush 50 contacts with an odd segment of ring C2, energizes relay SR so that its armature 53 is moved to its negative contact. The brushes may be stationary with the rings A .. F, Fig. 4 A2 .. D2 Fig. 9 rotated over them in synchronism with the transmission of the signals from the distant station.