Produce grader
AssigneeAMF Incorporated
InventorJohn R. Sherwood
Life of this patent
Estimating the term…
Abstract
A produce grader that includes first and second signal paths for producing first and second signals corresponding to respective detected characteristics of an article of produce being graded. Each signal path includes chopper means for converting d.c. signals to a.c. signals, a.c. amplifier means, and means including synchronous detector means for reconverting amplified a.c. signals to d.c. signals. The reconverted signals are compared and/or evaluated to establish a basis for grading. Means are provided for adjusting the duty cycle of the gating signal controlling at least one synchronous detector thereby adjusting the gain of the corresponding signal path and adjusting the calibration of the grader.
Claims6
In combination in an inspection signal path in which detector means produces a low level d.c. inspection signal and chopper means controlled by at least a first gating signal having a first duty cycle converts the low level d.c. signal to an a.c. signal which then is amplified in a.c. amplifier means, and wherein means including synchronous detector means reconvert the amplified a.c. signal to a d.c. signal, the improvement of gain control means for changing the gain of the inspection signal path, comprising
- means for producing a second gating signal having a second duty cycle which is adjustable from a maximum time period to a minimum time period, said maximum time period being no greater than said first duty cycle of said first gating signal, and
- means for coupling said second gating signal to said synchronous detector means for controlling its operation, whereby a change in said second duty cycle changes the magnitude of a reconverted d.c. signal thus changing the gain of said inspection signal path.
In a produce grader or the like having detector means for producing at least first and second d.c. signals corresponding to respective detected characteristics of an article of produce being graded, wherein the produce grader includes first and second respective signal paths for said two d.c. signals, wherein each signal path includes chopper means for chopping the d.c. signal into an a.c. signal, a.c. amplifier means for amplifying the a.c. signal, and means including synchronous detector means for reconverting the amplified a.c. signal to a d.c. signal, and wherein the reconverted d.c. signals in the signal paths are compared and/or evaluated according to a desired calibration to form a basis for grading an article, the improvement of adjustable calibration means for simply and reliably adjusting the calibration of the grader, said improvement comprising
- gating signal generating means for generating at least a first gating signal for controlling said chopper means in said signal paths and for generating second and third gating signals for controlling said synchronous detector means in the respective signal paths,
- said gating signal generating means including means for adjusting the time duration of at least one of said second and third gating signals, whereby the magnitude of at least one of said reconverted d.c. signals may be changed as a function of the duty cycle of its respective synchronous detector gating signal, thereby to change the calibration of said produce grader.
Dependencies are inferred from the claim text.