Cable compensator circuit for CCD video probe

• US 6,590,470 B1
• Filed: 06/13/2000
• Issued: 07/08/2003
• Est. Priority Date: 06/13/2000
• Status: Expired due to Term

• Current Assignee: Waygate Technologies USA LP (Baker Hughes Company)
• Original Assignee: Welch Allyn Incorporated
• Inventors: Burdick, Kenneth J.
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): JONES, STEPHEN E
• Application Number:
  US09/592,345
• Time in Patent Office: 1,120 Days
• Field of Search: 333/28.R, 356/241.1, 600/109
• US Class Current: 333/28.00R
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 23/66 Remote control of cameras or camera parts, e.g. by remote control devices
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/60 Noise processing, e.g. detecting, correcting, reducing or removing noise
• CPC Class Codes: H04N 25/745 Circuitry for generating timing or clock signals

Abstract

Picture noise in a CCD video probe is reduced by producing a faithful reproduction of a reset-gate signal received from a timing generator to an imager by using a cable compensator network. The network contains an RLC circuit which corrects the relative amplitude and phase of the various frequency components of the reset-gate signal. The precise values of the components in the RLC circuit are selected according to the attenuation and distortion characteristics of the coaxial cable connecting the drive electronics assembly from the imager assembly.

Claims

1. A cable compensator network which receives a reset-gate signal from a timing generator and provides said reset-gate signal to an imager, comprising:

an RLC circuit which corrects a relative amplitude and phase of a plurality of frequency components of said reset-gate signal; and

a low-pass filter which receives said reset-gate signal from said RLC circuit and outputs said reset-gate signal to said imager.

2. A network according to claim 1, wherein said RLC circuit includes:

a first branch including a first capacitor in series with a first resistor and a first inductor;

a second branch including a second resistor in parallel with a second capacitor;

a third branch including a third resistor; and

said first, second, and third branches being connected as a “

T”

, with said first branch positioned as a shunt to a reference potential.

3. A network according to claim 2, wherein said low-pass filter includes:

a second inductor connected in series to said third resistor;

a third capacitor connected between said second inductor and said reference potential; and

an output of said low-pass filter taken from between said second inductor and said third capacitor, said low-pass filter output being connected to said imager.

4. A network according to claim 3, further including a buffer and a fourth capacitor connected in series between said timing generator and said second branch.

5. A network according to claim 4, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

6. A network according to claim 2, wherein said third branch further includes a fourth capacitor in series with said third resistor.

7. A network according to claim 6, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

8. A network according to claim 2, wherein said third branch further includes a buffer in series with said third resistor.

9. A network according to claim 8, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

10. A network according to claim 1, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

11. A network according to claim 1, wherein said cable compensated by said network is at least 5 meters long.

12. A network according to claim 11, wherein said cable is 10 meters long.

13. A cable compensator network which receives a reset-gate signal from a timing generator and provides said reset-gate signal to an imager, comprising correcting means for performing phase and relative amplitude correction of said received reset-gate signal, wherein said correcting means boosts high frequency components of said received reset-gate signal relative to middle frequency components, limits attenuation of middle frequency components of said reset-gate signal, and passes low frequency components of said reset-gate signal.

14. A network according to claim 13, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

15. A network according to claim 13, further comprising means for filtering electromagnetic interference.

16. A network according to claim 15, wherein said network is a component of one of a borescope, bronchioscope, and angioscope.

17. A method for reducing picture noise in a CCD video probe that is a component of one of a borescope, bronchioscope, and angioscope, comprising the steps of:

receiving a reset-gate signal from a timing generator;

performing phase and relative amplitude correction of said received reset-gate signal;

wherein the step of performing includes the steps of boosting high frequency components of said received reset-gate signal relative to middle frequency components, and limiting attenuation of middle frequency components of said reset-gate signal; and

providing said corrected reset-gate signal to an imager in said CCD video probe.

18. A method according to claim 17, further including the step of passing low frequency components of said reset-gate signal to said imager.