发明名称 |
Digital automatic X-ray exposure control system |
摘要 |
A digital automatic X-ray exposure control system (22, 24, 26) includes a digital frequency modulated output signal circuit (40) generating a digital frequency modulated output signal (42) having a pulse rate that is frequency modulated in proportion to the level of an X-ray beam received at an ion chamber of an X-ray imaging apparatus. A digital input circuit (22) connected to the output circuit via a digital communication interface cable (26) receives the digital output signal and generates an exposure termination signal (80) for use by the X-ray imaging apparatus to interrupt the generation of the X-ray beam at a precise exposure level. The digital input circuit includes a digital counter circuit (70) for counting pulses in the output signal as a pulse count value that is compared against an exposure length parameter value (74) for generating a count match signal (76) based on a correspondence therebetween. A processor circuit (72) receives the count match signal and generates the exposure termination signal for extinguishing the X-ray beam. An X-ray film sensitivity circuit (64) and a digital short-time exposure compensation circuit (62) is included in the subject digital automatic exposure control system. The X-ray film sensitivity circuit includes a programmable clock divider circuit (96) for scaling the digital output signal in accordance with the screen sensitivity of the X-ray film. The digital short-time compensation circuit (62) includes a programmable frequency multiplier circuit (86) for multiplying the digital output signal by a clock multiplier scaling factor parameter during a brief programmable timing period.
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申请公布号 |
US6094473(A) |
申请公布日期 |
2000.07.25 |
申请号 |
US19980044541 |
申请日期 |
1998.03.19 |
申请人 |
PICKER INTERNATIONAL, INC. |
发明人 |
YU, PHILLIP H. |
分类号 |
H05G1/38;(IPC1-7):H05G1/44 |
主分类号 |
H05G1/38 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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