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.
sideband transmission extends out only a half megacycle away from the nominal frequency of the subcarrier; this fact, together with the practical requirements of receiver construction, dictates a subcarrier frequency in the vicinity of 3.5 me. The exact value of the subcarrier frequency must be, of course, an odd harmonic of one-half the line-scanning frequency; there is an additional minor advantage to be gained by making the difference between the subcarrier frequency and the frequency at which
sound is transmitted be also an odd multiple of one-half the line-scanning frequency. The choice of a subcarrier frequency of 3.579545 me satisfies these requirements without involving any change in the separation between picture and sound carriers as currently specified ; a decrease in line-scanning frequency of 0.1% from the presently specified value results from this choice but this decrease is negligible compared to the tolerance presently permitted to the line-scanning frequency itself.
*-COLOR SIGNAL
2 3 4 MC
COLOR SIGNAl*
01 2 3 4 MC COLOR CHANNEL
0 I 2 3 4 MC MONOCHROME CHANNEL EV
t
CHROMATICITY ONLY
Fig. 8. Elements of one form of receiver for the proposed NTSC signal.
Courtesy, Electronics (Ref. 9, Fig. 7).
IV. THE COLOR RECEIVER
Color-television receivers are not the direct concern of the NTSC; the Committee's primary objective is the specifying of a signal for color-television broadcasting which is believed to be a sound basis for the founding of a nationwide colortelevision service, and the recommending of that signal to the Federal Communications Commission after adequate testing. (Receivers are of interest to the Committee indirectly, however, for two important reasons: first, it is essential that the color-television signal
which the Committee recommends be suitable for use with receivers which can be built practically and sold commercially at prices which will interest the public; second, the verifying of the suitability of the Committee's proposed signal is an experimental process and must use both physical transmitters and physical receivers for that verification. A detailed discussion of receivers would therefore be inappropriate in this report of the work of the NTSC. A few words
A. V. Loughren: Color Television
331