We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
amplitude-modulation transmission is used for the picture signal in accordance with the FCC Rules cited in Specif. 4, above.
7. The sound transmission is by frequency modulation, with maximum deviation ±25 kc, and with pre-emphasis in accordance with a 75-jusec time constant. The frequency of the unmodulated sound carrier is 4.5 me ±1000 cycles above the frequency of the main picture carrier actually in use at the transmitter.
8. The radiated signals are horizontally polarized.
9. The power of the aural-signal transmitter is not less than 50% nor more than 70% of the peak power of the visualsignal transmitter.
Test Specifications — Group n
10. The color picture signal has the following composition:
Em = EY' + {^Q'sin (at + 33°)
+ £/'cos(orf + 33°)}
where
EQ' = 0.41 (EB' EY') *
+ 0.48 (ERr EY'}
Ei' = -0.27 (EB' EY')
+ 0.74 (E*1 EY')
EY' = 0.30 ER' -f 0.59 EG'
+ 0.11 Ett'
The phase of the color burst is sin (to/ + 180°)
Notes: For color-difference frequencies below 500 kc, the signal can be represented by
E. . E
sin o>t + (ER' —
cos at
\ f
In these expressions the symbols have the following significance:
Em is the total video voltage, corresponding to the scanning of a particular picture element, applied to the modulator of the picture transmitter.
EYr is the gamma-corrected voltage of
the monochrome (black-and-white) portion of the color picture signal, corresponding to the given picture element.
ER, EG'I and EB' are tne gammacorrected voltages corresponding to the red, green and blue signals intended for the color picture tube, during the scanning of the given picture element.
EQ' and EI are the two gamma-corrected orthogonal components of the chrominance signal corresponding, respectively, to the narrow-band and wideband axes.
w is 2r times the frequency of the chrominance subcarrier. The phase reference of this frequency is the color synchronizing signal (see Specif. 21 below) which corresponds to amplitude modulation of a continuous sine wave of the form sin (o>* -j 180°) where t is the time.
The portion of each expression between brackets represents the chrominance subcarrier signal which carries the chrominance information.
It is recommended that field-test receivers incorporate a reserve of 10-db gain in the chrominance channel over the gain required by the above expressions.
11. The primary colors referred to by ER', EG', and EBr have the following chromaticities in the CIE system of specification :
* y
Red (*) 0.67 0.33
Green (G) 0.21 0.71
Blue (B) 0.14 0.08
12. The color signal is so proportioned that when the chrominance subcarrier vanishes, the chromaticity reproduced corresponds to Illuminant C (x = 0.310, y = 0.316).
13. Gamma correction is such that the desired pictorial result shall be obtained on a display device having a transfer gradient (gamma exponent) of 2.75. The equipment used shall be capable of an overall transfer gradient of unity with a display device having a transfer gradient of 2.75. The voltages ET' ', ERr, EG', EB', EQ' and £/ hi the expression
334
April 1953 Journal of the SMPTE Vol. 60