公开(公告)号：DE1616385A1

公开(公告)日：1971-04-15

申请号：DE1616385

申请日：1968-01-03

Applicant: IBM

Inventor： JUN RICHARD BOGHOLTZ ,  DYM HERBERT

IPC: G02B27/00 ,  G01J1/42 ,  G01R23/00 ,  G01S7/483 ,  H01L27/14 ,  H01L31/02 ,  H04N3/12

Abstract: 1,172,927. Testing spectral distribution. INTERNATIONAL BUSINESS MACHINES CORP. Dec. 15, 1967 [Jan. 13, 1967], No.57207/67. Heading G1U. An apparatus for testing the spectral distribution of the frequency components of a signal waveform incorporates a number of bandpass filters 27-31 each tuned to a different bandwidth within a frequency spectrum of interest, to the common input line 24 of which the waveform is applied. The filters produce D. C. outputs representative of the amplitude of the corresponding waveform components. These outputs are adjusted by potentiometers 32-36 such that for a predetermined waveform the outputs from all the filters are the same. Comparators 44-48 compare the individual outputs from the potentiometers one with another to provide an output indication whenever a difference between the adjusted output signals of any two filters is detected. The arrangement is used in association with a device 10 for examining the spatial distribution of incident light, the device consisting of a combination of a photo-diode J1 and a simple diode J2 connected in opposition, across which a longitudinal potential gradiant from battery B to earth is applied. The arrangement is subjected to a voltage sweep from a generator 22, to provide a waveform on line 20 whose time variation corresponds to the spatial distribution of the incident light. This waveform is differentiated before being passed to the line 24, since the response is the summation of the photo-currents in the activated device, and the resulting signal analysed by means of the arrangement described above. The number of comparators required in the arrangement of Fig. 1 if a number of harmonics are to be examined will be considerable. The arrangement may be simplified by connecting the adjusted outputs from the filters in parallel to both positive and negative analogue OR diode circuits which respectively produce outputs corresponding to the highest and lowest signal from the filters. These two outputs are passed to a single comparator which produces an output when the difference between highest and lowest exceeds a threshold Fig. 2, (not shown).