| There are
three major TV systems in the world: NTSC, PAL and SECAM.
The major differences between the three systems can be
characterized by their differences on three frequencies: 1) Color subcarrier frequency 2) Vertical scanning frequency (the number of pictures per second) 3) Horizontal scanning frequency (the number of lines per picture) Table 1 shows the details.
|
| Video System Character |
NTSC(M) | PAL | SECAM | ||
| B,D,G & I | M | N | |||
| Color
Subcarrier Frequency |
3.579545 mHz |
4.43361875 mHz |
3.575611mHz | 3.582062mHz | for B:4.25000mHz for R:4.406250mHz |
| Horizontal
Scanning Frequency (Line Freq.) |
15.734kHz (525 Lines) |
15.625kHz (625 Lines) |
15.734 kHz (525 Lines) |
15.625kHz (625 Lines) |
15.625kHz |
| Vertical
Scanning Frequency (Field Freq.) |
60 Hz | 50 Hz | 60 Hz | 50 Hz | 50 Hz |
When converting from one video system to another system, it can be as simple as changing input video's color frequency to output video's color frequency or as complicate as changing all three frequencies (color, line and field). Simple or complicate, it depends on the degree of difference between input video and output video. If the two videos differs only on color frequency, e.g. PAL (B, D, G & I) and SECAM or NTSC and PAL M, then a simple analog conversion is sufficient. If they are different in all three frequencies, e.g. NTSC and PAL, or NTSC and SECAM, then a complicate digital conversion become necessary. The appropriate converter will allow you to view the converted signal on your TV plus record onto a suitable VCR. All Cypress digital converter converts the three frequencies and can be used with any kind of TV or VCR (for recording). All Cypress analog converters convert only color frequency, therefore are suitable for only simple conversions. When they are used in complicate conversions, the line and field frequencies are not converted means the output picture will become unrecordable and may roll constantly on the TV screen, Nevertheless, an analog converter can sometimes be used in complicate conversion, for viewing only not recording, if the TV connected to its output has a vertical hold control for adjusting the vertical frequency. Many old fashion TV has this functions, either manual or automatic control, hence they can be adjusted to match the converter output. The table below details the suitability of the different models.
|
| All digital models | Output is recordable, no
picture rolling or compression on the TV screen |
| Analog models CPM-100N,CP-100S CN-100P/M CS-100P,CPB-PN |
Output is recordable, no
picture rolling or compression on the TV screen |
| Analog models CN-100P/(RF) CP-100N CN-100P/N,CS-100N |
Output is
un-recordable, the picture might roll constantly on screen if TV has no V-hold adjustment Picture might be compressed (or extended) due to mis-match of line frequency between output and TV |
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