U3665M

Preliminary Information

TELEFUNKEN Semiconductors

Rev. A1, 17-Jul-96

1 (9)

Baseband Delay Line 64

ms (Improved Version)

Application

In TV sets, the integrated baseband delay line circuit is suitable for decoders with color-difference signal outputs

Description

The integrated delay line circuit U3665M is suitable for

all chroma decoders with baseband

color-difference

outputs.

It

is

suitable

for

PAL-,

SECAM-

and

NTSC-signals as well. The U3665M contains two

separate delay lines for processing (R–Y)-output and

(B–Y)-output separately. The delay is performed by inter-

nally switched capacitors. On-chip postfiltering avoids

the need for external filter components. In the case of the

U3665M, the postfilter is tuned to Bessel-characteristic.

A summing circuitry combines the information of

adjacent TV-lines, thus giving an interpolated sum for the

PAL-system, storing preceeding lines for the SECAM-

system and providing a comb-filtered output for

NTSC-signals. Due to internally generated timing,

synchronization is easily done by feeding a line-frequent

impulse (usually the SC-impulse) to the sync-input of

the IC.

Features

D One line delay time, addition of delayed and

non-delayed output signals

D Adjustment-free application, VCO without

external components

D Handles negative or positive color-difference

input signals

D Clamping of AC-coupled input signals

[

±(R–Y) and ±(B–Y)]

D Line-locked by the sandcastle pulse

D No crosstalk between SECAM color

carriers (diaphoty)

D Comb-filtering functions for NTSC color-

difference signals

D Correction of phase errors in the PAL system

SC detector

Line memory

Shift register

Line memory

Clamping

Clamping

S+H

S+H

LPF

LPF

+

+

Control

PLL

Clock generator

12

11

9

10

(B–Y)

(R–Y)

GND1

3 MHz

5

14

16

1

3

SC pulse

(B–Y)

(R–Y)

GND2

94 8846

"

"

"

"

Bias

Figure 1. Block diagram