25

D0Y

D0X

V

STV1601A

24

23

22

D1X

D1Y

EE

621

8-bit Parallel Data

10k

Ω

Figure 14 : 8-bit Parallel Input Data (ECL level)

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.

00

1

00

1

00

1

00

1

00

1

00

1

00

1

00

1

00

00

0

Input Data

Fixed Data

001

001

001

001

001

001

001

001

00

00

1

1

MSB

LSB

Input Order

Parallel Data after Conversion

Input Parallel Data

0

Figure 10 : Conversion from 8-bit TRS to

10-bit TRS

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 : x

D1

D2

D3

D4

D5

D6

D7

D8

D9

Figure 16 : (x

D1

D2

D3

D4

D5

D6

D7

D8

D9

Figure 17 : (x

To eliminate signal polarity of scrambled data, con-

version from NRZ to NRZI is performed (Figures 18

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

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

STV1601A

13/17