THE PROBLEM OF AUTOMATIC FINE TUNING IN TV AND VIDEO

RECORDERS

©1983 Mark B. Anstendig

If your TV or video cassette recorder (VCR) has an Automatic Fine Tuning system (AFT), you are probably viewing an unsharp, badly tuned picture. These AFT systems usually de-tune the station instead of locking it into the optimal setting. When, according to instructions, the station is first tuned manually to the optimal, sharpest setting with the most saturated colors and the AFT is then turned on, the picture becomes diffuse, the sharpness degraded, fine detail obliterated, and the colors more pastel and less saturated, usually to a substantial degree. Using a TV with a defective AFT is definitely not good for one's eyes, could affect one's health, and affects one's powers of visual discrimination. One very quickly becomes used to watching and accepting--even liking--a degraded, diffuse image.

The Anstendig Institute wants to make clear that what we call "defective" or "faulty" is not necessarily a malfunction of the AFT apparatus itself, which may be functioning within specifications. According to a SONY Corp. Field Engineer, it is the setting to which the AFT has been adjusted that is faulty, not the mechanism itself. The mechanism can be adjusted to seek the correct setting for most, but not all, channels.¹

Two points should be stressed: 1) with such an AFT that de-tunes the station, one cannot have a sharp picture or properly saturated colors, and 2) the name itself, "automatic fine tuning", is a misrepresentation of the way this circuit functions. The name gives the impression that the AFT will set the tuning even more precisely (finely) on the frequency of the station, when it actually does the opposite.

Since there must be millions of TV sets and VCRs with defective automatic tuning, one should check one's own TV or VCR.² An authorized service center can readjust the AFT to seek a more optimal setting. Be careful, because some TV sets and VCR's that have AFT do not have a separate AFT switch; the AFT is automatically turned on when the tuner-cover is closed.

A correctly functioning AFT is not meant to take the place of manual tuning. Its purpose is to lock the picture into the manually adjusted optimal setting and to keep the tuner on that setting in case the signal wanders. It should also fine-tune the manual settings if they are close, but not quite exact.

HOW TO CHECK YOUR AFT

To check whether your AFT is functioning correctly:

1) Choose a program with a subject that has fine detail and does not move a lot (the hair of a seated newscaster, for example).

2) With the AFT off, tune the set carefully by hand. First detune the set in the direction of a lower-numbered station until the picture turns black and white. Next, turn back in the other direction until the color returns. Continue until there is pronounced picture-noise in the image (picture noise is the criss-cross or zig-zag lines that appear on the screen).

3) Turn back in the other direction only to the point where the picture noise disappears and no further. (This should be repeated a few times to be sure.) The picture may still not be good when the noise disappears, in which case you need to improve your signal by getting the right antenna or, with cable, having the cable-installation adjusted.

4) While carefully watching the picture, turn on the AFT. If it is functioning correctly, the picture will either stay the same or improve very slightly. If it is not functioning correctly, the picture will either immediately or gradually change from the tuned setting to a more diffuse and less sharp setting. It is essential to watch very carefully, because the picture can detune so slowly that the change is difficult to notice while it is happening, even when the detuning is substantial. It is important to choose a moment when the subject that you are viewing is not moving when you turn on the AFT.

WHAT TO BE CAREFUL OF

With a good signal, the optimal setting is just before the point where picture-noise begins. But, if the signal is not good, there will be other problems such as double-image, harsh color tones (especially around the edges of the figures), and even picture noise, etc., at the optimal setting. Check this by watching the sharpness and the color tones critically. At the optimal setting, the image should be sharpest and have the most fine detail. The color tones should be as saturated as possible without becoming muddy. If it is difficult to view the screen easily while tuning the set, a mirror opposite the screen will allow viewing the image from a distance.

If the signal being received is bad, the falsely functioning AFT can give the impression that it has improved the picture because the diffusion of the image makes the picture noise and other aberrations less noticeable. But the picture itself is also degraded. The only defensible solution is to improve the signal. Having a competent technician check the reception is a one-time expense that cannot be too strongly recommended even if you do not have AFT problems. Few areas have reception that is correctly matched to the TV's input needs, and most areas have disturbances that can easily be eliminated. A reputable technician from your area will already be familiar with the problems.³

Since the faulty AFT degrades the image but does not obliterate it, one becomes accustomed to a diffuse, blurred picture quality. One assumes the original signal is that way and never realizes that it is wrong. Dealers tell us that, when they deliver newer sets with truly exact, quartz-synthesized tuning, many people are so conditioned to a poor, diffuse image quality that they insist the new set is wrong. A lack of discrimination in evaluating sensory perceptions is rampant in our society, and, with millions of people accustomed to degraded image quality, defective AFT's certainly are an important contributing factor.

¹ The functioning of the AFT can be substantially improved. But the methods used are undependable in that they are achieved subjectively by a technician using either a test-signal or, as in our case, the regular daily TV programs. One should carefully check the resulting settings and insist on further adjustment if necessary. At the time, the problem was not apparent to the technician at the SONY Service Center using SONY's test-signal. The Field Engineer first understood the problem and readjusted our AFT when he visited our premises and was able to see how our units functioned on real-life television programs. Even with correctly transmitted and received signals, an AFT is no substitute for a tuning mechanism that locks into the exact frequency of the station (generally called "Phase-lock-loop”, "quartz-synthesized”, and "frequency synthesis”).

² The Anstendig Institute has SONY products with faulty AFT's that are more than five years old.

³ See our paper "The Importance of Improving the Deplorable Quality of American Television.”

The Anstendig Institute is a non-profit, tax-exempt, research institute that was founded to investigate stress-producing vibrational influences in our lives and to pursue research in the fields of sight and sound; to provide material designed to help the public become aware of and understand stressful vibrational influences; to instruct the public in how to improve the quality of those influences in their lives; and to provide the research and explanations that are necessary for an understanding of how we see and hear.