| 摘要 |
1302070 Digital measurement SPERRY-SUN WELL SURVEYING CO 20 Nov 1970 [21 Nov 1969 (3)] 55276/70 Heading G4H In borehole apparatus digital measurements representing for example the angular position of a housing relative to two planes 90 degrees apart and the directional orientation of the housing relative to the earth's surface are transmitted to the surface by superimposing on an A.C. signal logical signals at a predetermined phase of the A.C. signal. As described the position of the housing relative to one plane is determined by counting pulses from a pulse generator (21, Fig. 4, not shown) in a 16-stage counter (113) for the time during which an AND gate (109) is enabled. The gate is opened when a slit (56, Fig. 2, not shown) in a shield (58) passes between a lamp (48) and a first photo-cell (53) on a motor-driven disc (39). The gate is closed when the lamp passes a second photo-cell (64) on the housing. Similar apparatus is used to measure the position of the housing in the second plane. The directional orientation of the housing is similarly determined except that a gyroscope (18, Fig. 3, not shown) is used to position a slit (95). The measurements in the three counters are then read out using a ring counter 116 (Fig. 5) pulsed by a scan drive 117 which delivers an output signal at the 90 degrees phase of the A.C. power signal applied to its input. The power signal is also applied to three gates, each associated with a counter, which are sequentially enabled by the output of the last stage of counter 116 to read out serially at the 270 degree phase of the A.C. signal first the contents of the first pendulum counter followed by the contents of the second pendulum counter and gyro counter. The resulting frame of 48 data bits are superimposed by a gate line bit insert circuit 134 (Fig. 6) on to the power signal at the 270 degree phase position, sync. signals being inserted at the 90 degree phase position before and after each frame by a circuit 128. At the surface a circuit 141 (Fig. 8, not shown) removes the sine wave and processing circuit (142) transmits the data bits to a shift register (148) the contents of which are fed to a store in a computer. The sync. bits are used to reset the shift register to zero. |
