U3666M
Preliminary Information
TELEFUNKEN Semiconductors
Rev. A1, 10-Feb-97
1 (9)
Baseband Delay Line 64 s
(Improved Version
of U3665M)
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 U3666M is suitable for
all chroma decoders with baseband color-difference
outputs. It is suitable for PAL-, SECAM- and
NTSC-signals as well. The U3666M 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
U3666M, 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
One line delay time, addition of delayed and
non-delayed output signals
Adjustment-free application, VCO without
external components
Handles negative or positive color-difference
input signals
Improved latch-up stability
Improved power supply rejection ratio (PSRR)
No crosstalk between SECAM color
carriers (diaphoty)
Comb-filtering functions for NTSC color-
difference signals
Correction of phase errors in the PAL system
SC detector
Line memory
Shift register
Line memory
Clamping
Clamping
V
Ref
V
Ref
S+H
S+H
LPF
LPF
+
+
Control
PLL
Clock generator
12
11
9
10
(B–Y)
(R–Y)
V
DD1
GND1
3 MHz
f
SC
5
14
16
1
3
SC pulse
(B–Y)
(R–Y)
V
DD2
GND2
94 8846
Bias
Figure 1. Block diagram