منحني الاستجابة لمراحل التردد المتوسط للمرئيات if .. كتاب التلفزيون الملون والعادي

6-3 Response curve for intermediate frequency phases of IF visuals:

The intermediate frequency phase response curve of the visuals represents the sum of the resonant circuit curves in the circuit. In Figure (6) (2) we notice that the frequencies between (344 - 37 min (Hz) are enlarged by approximately one level, and the enlargement decreases at the frequency (334 MHz) to reach the limits of (10%) in order to prevent the overlapping of sound and image in the same channel now. This frequency carries the audio signal for the same channel and completely suppresses the frequency 319 megahertz (MHz), which is the frequency of the audio carrier for the upper channel, and completely suppresses the frequency (40.4) megahertz, which is the middle frequency of the audio signal for the lower channel, and reduces the frequency amplification (389 megahertz). Hertz to about (50%) because this frequency is close to the frequency of 40.4 megahertz (MHz) and its signal will inevitably appear if it is left to grow at a high rate (above 50%) Figure .
The width of the amplification beam in the medium frequency circuits is (5) MHz and extends from (334 to 38.9 MHz) and includes the audio and video carrier. 7.7% of the maximum impedance of the circuit, and in Figure (6-6) we find that the bandwidth = BW.
It is equal to 0.4 MHz - and the width of the pass-through or amplification beam can be increased by using the reverse tuning method, in which two or more circuits are tuned at two or three suitable resonant frequencies, so the bandwidth increases, as well as the final response curve, as in Figure (6-7) and (6-8) .

A - response curve for one phase.

B - The response curve of two phases tuned at the same frequency, and it is noted that the resultant has a beamwidth less than the width of amplification beamwidth or passing one stage BW The beamwidth of one phase B 0.64 The beamwidth of two phases tuned at the same frequency