Patent GB-819524-A (GB)
Title: Improvements in or relating to apparatus for indicating or recording the listening or viewing habits of the users of radio receivers
IPC: H04H60/44
Filed: 1955-11-21
Abstract: 819,524. Radio receiving apparatus. NIELSEN CO. Ltd., A. C. (Nielson Co, A. C.). Nov. 21, 1955, No. 33320/55. Class 40 (5). A system for recording simultaneously on a single length of photographic film the transmitting stations received by a plurality of radio receivers as a function of time comprises means associated with each receiver for allotting a channel number to each station received and a matrix of impedance elements for converting the channel number of the received station to a binary coding and common recording apparatus which samples the output from each of the aforesaid means and records it in a binary code form on photographic film together with time marker indications. The apparatus associated with each receiver 10 comprises a position switch 15 and a binary converter 16 and it is associated with the power supply of the receiver through a connector 40 in such a manner that the receiver can be energized only when the associated apparatus is properly connected to the receiver. Rotation of the tuning knob 31 of each receiver causes the rotation of a corresponding shaft 43 in the position switch 15 through a mechanical linkage, the shaft 43 being provided with a plurality of angularly spaced contact making elements so that when the receiver is tuned to any one of a number of predetermined transmitting stations the output of an energizing transformer 54 is applied through a corresponding contact making element to one input conductor of the binary converter 16. In the construction shown the binary converter comprises fifteen input conductors which are interconnected, by a matrix of resistors, with four output conductors 110, 111, 112, 113 selected ones of which carry voltages of significant amplitude according to a binary code representation of the station channel number corresponding to the input conductor of the binary converter of which the circuit is completed by means of one of the contact-making elements. The potentials carried by the output conductors of the binary converter are applied to respective stationary contacts of a commutator switch 21, the corresponding outputs from the binary converters associated with other radio receivers in the system being connected to other contacts of the commutator switch to which no connection is shown in Fig. 2b. The switch arm 162 is rotated continuously at one revolution per minute by motor 160 which also drives the apertured disc 164 at the same rate. Signals picked up by the rotating arm 162 are applied to a thyratron amplifier 23 and thence to lamp 24 light from which shines through the apertured disc 25 on to the photographic film 143, so that on each complete revolution of the arm 162 and disc 25 a series of marks is made across the width of the film 143 corresponding to the binary codings of the. station received by each one of the receivers forming part of the system. In addition time markers are provided on the film by means of potentials applied to the contacts HM, MM and DM and controlled by switching apparatus 141 driven by a mechanical clock which is continuously wound through a slipping clutch by motor 199. The potentials applied to the three contacts are such that the contact MM produces minute marks except at the end of each hour when instead a mark is produced by the contact HM, the hour mark being omitted in the 24th hour of each day and replaced by a day mark provided by the contact DM except on the seventh day of each week when the day marker is inoperative- and the hour marker remains operative. In order to allow for power failures relay 185 is provided so that should the power fail contacts 185b are closed, the relay being such that these contacts remain closed for several minutes after power is restored. Lamp 24 thus remains continuously lit during this period whereby the whole width of the film is illuminated for several rotations of the disc 25 through the long slot 165 and the record on the film consequently indicates the occurrence of the power failure.