Patent GB-720097-A (GB)
Title: Electrical apparatus for measuring and recording plural concurrent phenomena
IPC: G01R13/04
Filed: 1951-08-09
Abstract: 720,097. Current and voltage measuring and detecting; frequency measuring. TELEPHONUND TELEGRAPHENFABRIKS AKT.-GES KAPSCH & SOHNE IN WIEN. Aug. 9, 1951 [July 18, 1951], No. 18804/51. Class 37. [Also in Group XXXVIII] Electrical apparatus for recording on a record surface @lating to a number of concurrent physical phenomena supplied to the apparatus from plural sources in the form of successive electric impulses, comprises a recording member traversed across the record surface and movable toward and away therefrom, electrical means for displacing the recording member during its traverse to apply it to the record surface, selecting means adjustable in synchronism with the traversing movement of the recording member to successively transmit the appropriate successive signal impulses from the several sources to the means for displacing the recording member so as to apply the latter to the record surface to record linear traces thereon having lengths corresponding to the times during which the respective impulses are effective to maintain the recording member applied to the record surface, and line feed mechanism for advancing the record surface after a line of traces has been applied thereto. Fig. 1 shows apparatus for successively recording multiple concurrent phenomena wherein motor-driven cam 5 and roller 5a carried by pushrod 6, reciprocates recording device 9 carrying stylus 10 over chart 11 traversed at right angles to the reciprocation. Rod 6 is extended as rack 7 engaging pinion 8 to rotate shaft 2 synchronously with the reciprocation to sweep the tuning of a radio receiver 3 through its range and traverse contact arm 4 of a rotary switch over a bank of multiple contacts to successively select circuits for testing. The amplified output of the radio receiver when selected by changeover switch 12 energizes stylus 10 to mark a linear trace mechanically, chemically, or optically on the chart 11 whose length represents the period of energization so that a trace of length dependent on the signal intensity is recorded when the input contains a signal at the frequency corresponding to the instantaneous tuning frequency of the receiver. Alternatively the stylus is successively energized by the signals on the contacts engaged by arm 4 and linear traces are recorded representing the durations of the signals on the successive contacts. After each complete traverse of the stylus across the chart, recording is suppressed while it is returned to its starting point, and the chart is simultaneously advanced by the width of one line after which the cycle recommences. Time graduations 19 may be imposed on the record by the periodic injection of clockcontrolled signals maintaining the stylus in contact with the chart during an entire line traverse, or the chart may be calibrated in correspondence with successive line traverses. The chart movement and calibration may be made dependent on other quantities than time ; e.g. distance coverage or numerical counting. Discontinuous phenomena as shown by traces 14 and 18 (Fig. 3) may be correlated while the curve 15 representing e.g. input frequency variations of the radio receiver 3 may be interpreted with reference to superimposed reference traces a to e recorded at regularly recurring time intervals. Traces 16, 17 record recurring signals of variable intensities represented by the trace lengths, derived from radio receiver 3 scanning a range of frequencies; whose output when passing through a signal band persists at a level exceeding the threshold of operation of the recording device for a time dependent on the signal intensity, by reason of the shape of the receiver tuning curve. The output of a directional radio receiver over 360 degrees may be similarly recorded (Fig. 4) by tuning it over its entire frequency range during each traverse and varying its direction of reception by a predetermined angle for each line shift, the chart being graduated through 360 degrees in its direction of motion, so that the traces 22, 23 produced by signals from different stations are shown in positions corresponding to their respective frequencies and bearings. Alternatively the outputs of different predetermined frequency channels may be applied to the respective contacts of the selector switch 4 while the direction of response is varied for successive lines, or the direction of response may be varied several times through 360 degrees during one traverse for a single frequency channel so that plural traces 24 appear against a horizontal angular scale defined by vertical lines 19 corresponding to 0 degrees and 360 degrees in the directional rotation (Fig. 5). Fig. 6 shows a complete recording apparatus in which a chart 32 travels from a supply roll 47 to a rewind roll 49 over a recording roll 31 under a stylus 30 carried by a flexible arm 29 of a recording carriage 33 which is reciprocated laterally along a guide rod 34 by a stud 35 engaging oppositely directed cross-threaded guide grooves of a traversing cylinder 36 rotated by a motor 37 geared to a drive shaft 57. The arm 29 may be depressed to engage the stylus with the chart at any point of its travel by a rocking bar 28 operated by an electromagnet 27 energized alternatively through switch 12 from the output amplifier of a radio receiver 3 or from arm 60 of a rotary selector switch. Recording is effected during travel from left to right and the stylus is held out of contact with the chart during the return movement at the end of which arm 40 of the carriage displaces member 41 along shaft 40a against a return spring to operate pawl 42 and ratchet 43 to shift the recording drum 31 and the chart through a predetermined distance. The tuning capacitor 2a of the receiver is swept through its range in correspondence with the recording traverse by shaft 50, driven by spring- loaded cylinder 54 carrying on its surface shaped template strips 53 engaging a roller carried by an arm 51 of the recording carriage so that any desired law may connect the tuned frequency of the receiver with the position of the recording stylus, according to the shape of the template used, which alternatively may take the form of a groove milled into the cylinder periphery, Fig. 7 (not shown). When the receiver is tuned to a particular input signal exceeding a threshold amplitude, its output energizes the electromagnet 27 which applies the stylus to the chart for so long as the receiver remains responsive to the signal, so that a horizontal line is recorded whose length depends on the frequency band covered by the signal and by the intensity thereof as explained. Alternatively the operating electromagnet may be energized from individual circuits successively selected in dependence on the instantaneous position of the stylus during its traverse. Banks 58a, b, c, d of contacts connected to circuits to be measured are engaged by contact arms 56a, b, c, d rotated by the shaft 57 of the traversing cylinder 36; arms 56a, c being 180 degrees displaced from arms 56b, d and the several contact arms being respectively and sequentially connected to arcuate contacts a<SP>1</SP>, b<SP>1</SP>, c<SP>1</SP>, d<SP>1</SP>, engaged by angularly spaced selector contact arms 60, 60<SP>1</SP> rotated through gearing at half the speed of shaft 57 and connected to energize the electromagnet so that during one traverse of the stylus over the chart all the contacts of the banks 58a, b, c, d are selectively and sequentially connected to operate the electromagnet in accordance with the energization of the test circuit associated with each particular contact. Fixed styli 70 bearing continuously on the chart produce reference lines 19<SP>1</SP>. The shaft 57 is provided with an arresting device comprising a notched cam 64 engageable by a detent 66 normally held disengaged when electromagnet 67 is energized but released on de-energization to stop the stylus traverse. The apparatus is stated to be applicable to the successive testing of telephone lines, the monitoring of transmitted frequency bands in carrier telephone working, to the supervision of electrically measured quantities involved in assembly line production, and to the supervision of multiple electrically measurable time varying temperatures. Recording may be effected photoelectrically by varying the intensity of a recording light beam.