Technology advancement has always been about research
and development in all fields related to the concept, be it any combination of mechanical, electrical,
programming, implementation, usage, or training. Television went fundamentally unchanged from the time
of its commercial implementation in the early part of the last century until the advent of plasma screens
(i.e., no more raster-scanned CRTs) in the latter part of the last century.
Color tubes added complexity to the signal, but it was still an analog signal. Then came digital broadcasting
in the early part of this century. The same sort of evolution occurred with telephones and to some extent
with radio. This Television I.Q. Quiz from a 1948 edition of Radio & Television News magazine will
give you some insight into how TVs (and your computer monitor) used to
Television I.Q. Quiz
By Ed. Bukstein
Northwestern Vocational Institute
1. The frequency of horizontal scanning in the standard 525
line television picture is (a) 60 (b) 525 (c) 15,750 (d) 31,500 c.p.s.
2. The control which varies the bias on the cathode-ray tube is (a) contrast (b) brightness (c) focus
(d) vertical hold.
3. The purpose of interlacing is to (a) reduce flicker (b) reduce ghost images (c) make blanking
unnecessary (d) make scanning unnecessary.
4; The linearity control is located in the (a) deflection circuit (b) sound i.f. amplifier (c) sync
clipper stage (d) picture i.f. amplifier.
5. Under present-day standards, the bandwidth occupied by a television signal is (a) 75 kc. (b) 10
mc. (c) 525 mc. (d) 6 mc.
6. The width control varies the amplitude of the (a) sync pulses (b) horizontal saw-tooth (c) vertical
saw-tooth (d) blanking pulses.
7. Ghost images are caused by (a) power supply ripple (b) audio signals reaching the grid of the
picture tube (c) reflected signals (d) line voltage variations.
8. The purpose of the blanking pulses is to (a) synchronize the vertical oscillator (b) eliminate
retrace on picture tube (c) reduce ghost images (d) prevent arcing in high voltage power supply.
9. The picture carrier is separated from the sound carrier by (a) 72 mc. (b) 21.5 mc. (c) 75 kc.
(d) 4.5 mc.
10. The vertical oscillator frequency is (a) 60 (b)30 (c) 525 (d) 15,750 c.p.s.
11. The circuit shown in Fig. 1 is a (a) sync separator (b) ratio
discriminator (c) blocking oscillator (d) FM limiter.
12. The field frequency of standard television broadcasts is (a) 110 (b) 60 (c) 21.5 (d) 30.
13. The frequency of the horizontal oscillator is (a) 30 (b) 60 (c) 525 (d) 15,750 c.p.s.
14. Which of the voltage waveforms shown in Fig. 2 is required to pass a saw-tooth current through
a deflection coil?
15. The circuit shown in Fig. 3 is an (a) integration circuit (b) differentiation circuit.
16. The frame frequency used in standard television broadcasts
is (a) 30 (b) 60 (c) 525 (d) 31,500 c.p.s.
17. Aspect ratio is a measure of (a) image width to image height (b) transmitting antenna height
to receiving antenna height (c) deviation of an FM signal (d) skip distance.
18. The mosaic is part of the (a) iconoscope (b) kinescope (c) damping tube (d) sync clipper.
19. The hold control is located in the (a) r.f. amplifier (b) sound i.f. amplifier (c) deflection
circuit (d) PM detector.
20. The diode connected to the horizontal deflection coils is known as the (a) sync clipper (b) damping
tube (c) video amplifier (d) video detector.
Answers to "TV Quiz"
19-20 correct ..... excellent
16-18 correct ..... very good
13-15 correct ..... good
10-12 correct ..... fair
9 or less ..... poor
Posted October 3, 2016