U4223B ATMEL Corporation, U4223B Datasheet - Page 15

• Manufacturer Part Number: U4223B
• Description: Time-code Receiver With A/d Converter
• Manufacturer: ATMEL Corporation

Rev. A7, 06-Mar-01
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).
Example: UTC 18.42 h
seconds
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 26.
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 markers (P0 thru P5) and 1 frame-
reference marker with reduced carrier amplitude of
800 ms duration.
40
20 10
45
year
50
hours
55
8
4
0
2
daylight savings time bits
leap second warning bit
leap year indicator bit
“0” = non leap year
“1” = leap year
U4223B
Time frame
5
1
P2
10
15 (18)