| 摘要 |
A seconds generator has a radio receiver (10) adapted to receive a signal from a Standard Time Transmitter, the signal being in the form of a carrier wave which is keyed on and off to provide seconds markers, the keying being in a form which provides a first state (on or off) lasting for at least a shorter seconds marker period (31) after a second state (off or on) lasting for at least a longer seconds marker period (32). The receiver (10) has an output in the form of a substantially two-level signal going between a "carrier on" and a "carrier off" state. A seconds detector logic circuit (12) intakes and analyses the output from the receiver (10) and controls a display unit (14) which displays a decimal count of seconds (17) and a confidence marker (18). The seconds detector logic circuit (12) is adapted to monitor the output from the receiver (10) firstly to detect the seconds markers (31, 32) and to convey to the display unit (14) instructions to upgrade the count in seconds, and secondly to detect any discontinuity in the seconds markers (31, 32) and, on detection of any discontinuity, to instruct the display unit (14) to actuate the confidence marker (18). <IMAGE> |
