Video IF circuit TV
Video IF circuit The main function of the video IF is to change the 38.0 MHz IF signal into the CVBS signal which later fed into the sound and video to the chroma. VIF section consists of a series as follows: IF amplifier This section serves to strengthen the signal until the signal level is required. IF amplifier is equipped with AGC (Automatic Gain Controller) which controls the strengthening of the IF amplifier so that a constant amplitude output video. Amplifier frequency range from 32 ~ 60 MHz makes this amplifier suitable for applications multistandar. PLL demodulator and VCO (voltage control oscillator) IF signal is separated with the help of PLL detector. PLL detector produces a phase reference signal with the IF signal carrier and about 60 KHz bandwidth is determined by PLL loopfilter pin 37. Obtained by comparing the frequency demodulation reference signal with the incoming IF signal. Are required reference frequency (38.0 MHz) generated by the VCO. Appropriate VCO frequency...