Patent GB-783089-A (GB)
Title: An improved system of telecommunication
IPC: G05B19/16
Filed: 1953-12-11
Abstract: 783,089. Type-printing telegraphy. SOC. ASSERVELEC. Dec. 11, 1953 [Dec. 26, 1952], No. 34534/53. Class 40 (3). [Also in Group XXXVIII] A system for the remote or time-delayed control of an electrically-operated machine or apparatus, such as a printer or perforator, by means of a magnetic storage carrier in which, at the transmitting end, information of control signals are recorded on the carrier in the form of individual frequencies, or said frequencies are transmitted and recorded on a magnetic carrier at the distant station, and in which the frequencies reproduced from the magnetic carrier are applied to frequency-selective means to effect the selective electrical operation of the machine or apparatus to be controlled, employs means for recording simultaneously with the individual frequencies a separate (reference) frequency which, after reproduction, is used to maintain a fixed relationship between the speeds of recording the information frequencies at the sending or receiving end and the reproduction thereof at the receiving end. Transmitter. The operation of a key closes a contact K1 . . . Kn operating an associated relay E1 . . . En and also a universal contact Kc operating a relay Ea and a relay R 1 after a slight delay. The operation of relay Ea and a relay E1 . . . En frees the blade La and one of the associated blades L1 . . . Ln to generate an operating frequency Fa and a corresponding selection frequency in a circuit comprising contact r12, an amplifier A and the primary winding of a transformer T. Contact r11 closes the circuit of a relay R2 which operates after a delay, e.g. 20 ms., and contact r2 closes the circuit of relay R3 which energizes after a further delay, e.g. 20 ms., to operate contact r3 which opens the circuit to the amplifier A so that the frequencies are transmitted or passed to the recording circuit C6 for a fixed time independently of the retention period of the key. The frequencies may be recorded on a magnetic wire or tape at the transmitter station or transmitted to a receiving station where they are recorded, and subsequently reproduced for the operation of receiving apparatus. A control frequency Fr from a generator G is also recorded on the magnetic carrier, or transmitted directly. Receiving arrangement. The control frequency separated by the appropriate filter section of the detector D is applied to vibrating blades L91, L92, L93, the blade L93 being normally operated to make valve T93 conductive and operate relay R93 opening contacts r931, r932, r933. If the frequency reproduced is outside predetermined limits, L91 or L92 is operated so that valve T91 or T92 operates relay R91 or R92 and contacts r91 or r92 bring in a motor-control circuit C81 or C82 which accelerates or retards the motor M driving the tape from which the frequencies are reproduced by the pick-up PU. If the control frequency is entirely missing for a period, relay R94 operates after a delay and at contact r914 opens the circuit of the motor M. Operated contact r942 illuminates lamp 1# indicating normal operation, whilst released contact r942 lights lamp 1a indicating that the motor has been stopped. The frequency corresponding to an operated key contact K1 . . . Kn Kc is applied from the appropriate filter section of the detector D to vibrating blades L<SP>1</SP>1 . . . L<SP>1</SP>n selectively energizing a valve T<SP>1</SP>1 . . . T<SP>1</SP>n and the corresponding relay R<SP>1</SP>1 . . . R<SP>1</SP>n to control the desired operation in a printing or perforating machine P. The operating frequency generated by the blade La of the transmitter is detected by band-pass filter H when the tape is moving at approximately the correct speed and makes a valve Ta conducting so that a relay R12 operates after a slight delay. At contact r121 a circuit is completed for the selected operating magnet of the machine P, and at contact r122 a circuit is completed for relay R10 which operates after a delay, and at contact r101 opens the circuits of relays R<SP>1</SP>1 . . . R<SP>1</SP>n to terminate the printing or perforating operation. Also the operation of contacts r123, r102 energizes relay Ea which temporarily retains the blades L<SP>1</SP>1 . . . Lln against vibration, the relays R12, R10 and Ea being released when the operating frequency Fa terminates so that the receiving apparatus is ready to respond to the subsequent signal.