US Patent 6995786 Electronic endoscope forming still image by double-speed reading

To provide a timing generator which generates a first reference signal at a standard speed of approximately 14 MHz and a second reference signal operating at approximately 28 MHz which is double the standard speed and forms a moving image based on the first reference signal, reads, when a freeze switch is operated, an image pickup signal based on the second reference signal operating at the double speed and writes this signal into the memory 36 at the same speed. Then, by reading this still image signal from the memory at the standard speed, the still image is displayed on the monitor. Thereby, the need for setting a conventional light shielding period can be eliminated.