£1,200.00
This very rare CRT tube is perfect for any exhibition on Communication History and helps visually show the first successful step for converting analogue data into digital signals. Marked as a developmental tube by the UK’s General Electric Company, it dates to around 1948-52 and should technically be called an ‘electron beam deflection tube for pulse code modulation’ (GEC model: Kgx 3d).
In November 1947 Frank Grey and Raymond Sears of Bell Labs patented ground breaking apparatus for using a cathode ray and encoding plate to convert analogue signals into binary. This was then published in the Bell Systems Technical Journal 27:1 of January 1948 and a link to that article can be read here. It is that system which this GEC tube clearly follows.
During the late 1940s to early 1950s the CRT research department at GEC were working on, amongst other things, systems to improve the efficiency of the telephone, television and radio networks here in the UK. When Sears and Grey announced their new invention it would have been natural for the group to jump quickly onto the new Pulse Code Modulation technology to apply to their projects. However probably due to patent rights instead of just using the exact tube design by Sears, they instead appear to have quickly adapted one of their existing monoscope tube designs.
This tube is offered in good original condition with some light flaking to the internal colloidal graphite and some external flaking also. It measures 40cm long and the end is 16cm in diameter.
Obviously it is offered untested and being a CRT will be packed extremely carefully and securely for transport.
1 in stock
