Browse Prior Art Database

Camera Focusing System

IP.com Disclosure Number: IPCOM000092513D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Bederman, S: AUTHOR

Abstract

The camera focusing system can be operated in either an automatic or semiautomatic mode.

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Camera Focusing System

The camera focusing system can be operated in either an automatic or semiautomatic mode.

In operation, the sweep frequency of sawtooth generator 10 and the operating frequencies of multivibrator 12 are such that, during the main sweep portion of the oscillator operation, its frequency changes at a rate of 150 KC per second. This frequency variation is converted by power output stage 14 and transducer 16 into a sound wave. The latter is bounced off the object being focused on 18 and picked up by receiving transducer 20. Assuming that sound travels at the rate of 1,100 feet per second, the returning echoes picked up by transducer 20 differ in frequency from the currently transmitted frequency in accordance with this table.

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The received signal is applied through amplifier 22 as one input to mixer 24. The other input to mixer 24 is the output from oscillator 12. The beat output from mixer 24 is passed through gate 26 to one input of mixer 28. Gate 26 is conditioned except for approximately 30 ms. after the start of the flyback period of sawtooth generator 10. Potentiometer 30 is coupled to the focusing screw for the camera lens system. As the focus is adjusted, either manually or under servo control, the output from variable audio frequency oscillator 32 varies in accordance with the setting of potentiometer 30. The output from oscillator 32 is applied as a second input to mixer 28. The focusing operation is terminated when a ze...