ELECTRONIC WEB TIMER

1,235,956. Tape counter. AMPEX CORP. 29 Sept., 1969 [13 Dec., 1968], No. 47701/69. Headings G4H and G5R. An electrical counter for a magnetic video tape (or other web-form record) produces binary signals indicating the position of the tape and decodes and displays these signals. Pulses corresponding to tape movement may be produced by a tachometer 31 coupled to the tape drive, or by a transducer (14, Fig. 4, not shown) monitoring control pulses on the tape, or by an address process unit 37 if the tape carries an address track. A divider 32 produces one pulse per frame or per second of tape running time. These pulses are then counted by a " clock " 36 (also Fig. 3, not shown) whose binary output is decoded at 38 and displayed on at least one display 40 in terms of elapsed hours, minutes, seconds and frames. A direction sensor 33 controls the clock direction, and ensures that when the tape is reversed the divider 32 produces pulses at the same points on the tape as in the forward direction. If a tachometer is used, a standard selector 34 controls the divider 32 according to the preselected tape speed and number of frames per second. If an address process unit 37 is used and has a binary output, the clock 36 is not used. For editing purposes a selection switch assembly 48 is provided which can be set to produce a binary code output indicating a desired stop time. This output is compared with the binary clock output in a comparator 46, and a coincidence signal may control the tape transport or other system.