Patent GB-1244684-A (GB)
Title: Method and system for reproducing, storing or recovering a time varying signal waveform
Inventor: FINNEY WILLIAM JETTON
IPC: G01R13/04
Filed: 1969-09-30
Abstract: 1,244,684. Electrolytic meters. W. J. FINNEY. Sept. 30, 1969, No.48079/69. Heading G1Q. A representation of a time varying signal waveform is stored by producing a solid body having successive superimposed layers of material with particular different layers having compositions representing particular parts of the waveform. The forces acting on an electrolyte may be varied in accordance with a time varying signal waveform to be recorded to control the composition of a solid body deposited from the electrolyte. The stored waveform is recovered by electrolytically dissolving the successive layers progressively. In one arrangement, an electrolytic cell is used containing a relatively large volume of electrolyte whose concentration effectively remains constant, while two alloyed materials are used for one electrode, the materials being deposited on the other electrode in a ratio dependent on the current magnitude through the cell. The dependence of the ratio on current is due to the differences in electro-chemical potential of the two materials, ionic mobility and solubility all of which effect the thermodynamic equilibrium established. In the arrangement of Fig. 1, a cell 1 has a platinum storage electrode 2 with its endface 2' just exposed to the electrolyte 4. The anode is a 50/50 alloy of cobalt and nickel, those elements being chosen as having similar lattice structures, close electro-chemical potentials, atomic radius and anodic activity, and is preferably a single crystal. The electrolyte may be the chloride salts of these metals. Current is applied to the cell from a source 6 under the control of an information source 7. Layers 2<11> are built up on the anode face 2<1>, each having a composition depending on the related current magnitude. To read out the information stored, a constant current is passed through the cell in the opposite direction. As each layer is exposed a voltage is developed across the cell related to the electro-chemical potential of the given layer, and this can be detected across a resistor in parallel with the cell. In an embodiment operationally similar to that shown in Fig. 1, the cell is hermetically sealed and the electrolyte is maintained only between the faces of the two electrodes, by surface tension, the rest of the cell being filled only with the electrolyte vapour, Fig. 3 (not shown). In a further embodiment, Fig. 4, the cell is again hermetically sealed, the opposing faces of the two electrodes 2, 3 being of similar area, and a small amount of electrolyte 4 being self maintained between them by surface tension. A ring type electrode 5 is incorporated between the two main electrodes. The electrode 5 is of pure nickel or cobalt, while the electrode 3 may be an alloy as before, or a different pure metal (cobalt or nickel respectively). Changes in the ratio of current flowing in the electrodes 3 and 5 cause changes in the ion concentration in the electrolyte and changes in the constitution of the deposited material on the storage electrode. In another arrangement, Fig. 5 (not shown), the storage electrode 2 may be vibrated in accordance with the information to be recorded while the cell passes a steady current. The vibration changes the composition of the layers built up on the electrode in accordance with the information to be stored. The vibration may be applied by a magnetostrictive arrangement applied to the electrode 2 or by flexing the wall of the cell. In some applications it is advantageous to plate on a barrier layer among the different layers on the storage electrode 2, e.g. in pulse position modulation recording. The barrier layers prevent dissolution of the storage electrode when they come to the surface until a special process is applied. To read out a system wherein the layers on the electrode 2 include ones with a high nickel content, the electrolyte is changed to sulphate and the supply 6, Fig. 6, reversed. When a barrier layer is reached, a large voltage pulse appears across the resistor R<1> and is applied to a control 30 which causes an oscillator 32 to operate to magnetostrictively vibrate the rod 2. This breaks down the barriers and enables read-out to continue. If the recording is of pulse position, the pulses obtained at read-out occur at times corresponding to their position in the input waveform. Instead of functioning automatically, the equipment might require operator intervention to break down the barrier.