STV1601A Просмотр технического описания (PDF) - STMicroelectronics
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STV1601A Datasheet PDF : 17 Pages
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Figure 14 : 8-bit Parallel Input Data (ECL level)
STV1601A
Figure 16 : (x9 + x4 +1) Basic Scrambling Circuit
STV1601A
6
21
D1X D1Y D0X D0Y
22 23 24 25
D1 D2 D3 D4 D5 D6 D7 D8 D9
Figure 17 : (x9 + x4 +1) Basic Scrambling Circuit
8-bit Parallel Data
10kΩ
VEE
D1 D2 D3 D4 D6 D7 D8 D9
D5
The conversion algorithm detects 2 successive
000H words and sets the two LSBs of the previous
word, which is supposed to be FF, according to the
standard.
Figure 10 : Conversion from 8-bit TRS to
10-bit TRS
Input Order
Input Data
Fixed Data
001
001
001
001
001
001
001
001
000
000
MSB
LSB
001
001
001
001
001
001
001
001
001
001
Input Parallel Data
Parallel Data after Conversion
Conversion in the case of more than three succes-
sive ”000H” words.
If more than 3 consecutive words of 000 in D1
standard, or 4 consecutive words of 000 in D2
standard occur at the parallel input (illegal accord-
ing to the standard), thus no proper operation is
possible.
5. Scrambling and NRZ to NRZI conversion
Figures 16 and 17 show the scrambling circuit, the
scrambling polynomial is as follows : x9 + x4 + 1.
To eliminate signal polarity of scrambled data, con-
version from NRZ to NRZI is performed (Figures18
and 19).
Therefore, the polarity for output distribution or
receiving is not needed. This allows easy system
design. The NRZ to NRZI polynominal is x + 1.
VCO temperature compensation and oscillation
frequency adjustment
VCO oscillation frequency depends on the tem-
perature as shown in Figures 22 and 23 ”Repre-
sentative characteristics examples”. Within the
normal range of operation, frequency increases
with temperature. FV voltage remains almost con-
stant regardless of temperature. Figure 20 shows
an example of a temperature compensation circuit
using a diode (transistor with C-B diode short-cir-
cuited) and a resistor connected between FV and
VEE. Examplesof representativecharacteristics for
various temperatures are shown in Figures 22 and
23 concerning oscillation frequency and PLL pull-in
range (signal frequency 270, 177 and 143MHz).
VCO free running frequency adjustment
VCO free running frequency adjustment is per-
formed at room temperature.
If TN1 is set High, VCO free runs. Wait for 5 to
10 minutes after turning power supply ON (warm
up time). While monitoring PCK output (Pin 36)
adjust the signal frequency (within ± 1%) with the
variable resistor connected between FV and VEE.
13/17
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