t4225b ATMEL Corporation, t4225b Datasheet - Page 14

• Manufacturer Part Number: t4225b
• Description: Low-cost Time-code Receiver
• Manufacturer: ATMEL Corporation

Information on the US Transmitter
Station: WWVB
Frequency 60 kHz
Transmitting power 40 kW
Modulation
The carrier amplitude is reduced by 10 dB at the begin-
ning of each second and is restored within 500 ms (binary
one) or within 200 ms (binary zero).
T4225B
Example: UTC 18.42 h
seconds
14 (16)
0
P0
minutes
0
5
1
40 20 10
Frame-reference marker
10
2
3
hours
15
4
minutes
20
5
8
Time frame
6
Time frame 1 minute
25
( index count 1 second)
4
7
days
2
30
8
1 P1
9 10 11 12 13 14 15 16 17 18 19 20
Figure 25.
35
sign correction
UTI UTI
Location: Fort Collins
Geographical coordinates: 40 __ 40’N, 105 __ 03’W
Time of transmission: permanent
Time-Code Format
The time-code format consists of 1-minute time frames.
A time frame contains BCD-coded information of
minutes, hours, days and year. In addition, there are
6 position-identifier
1 frame-reference marker with reduced carrier amplitude
of 800 ms duration.
40
20 10
45
year
50
hours
55
markers
8
4
0
2
daylight savings time bits
leap second warning bit
leap year indicator bit
“0” = non leap year
“1” = leap year
(P0
Rev. A3, 03-Dec-98
Time frame
5
1
thru
P2
93 7529 e
10
P5)
and