发明名称 |
Apparatus for detecting the frequency of an input signal by counting pulses during an input signal cycle |
摘要 |
An apparatus for detecting frequency of an input signal by counting the pulses of a reference signal of a predetermined frequency within one cycle of the input signal is disclosed. The apparatus includes a first and a second latch for latching the number of pulses of the reference signal for two consecutive periods of the input signal. In response to the reference signal, a comparator is used to compare the output value of the first and the second latch. When they are different, a flip-flop generates an interrupt signal to a microprocessor. The microprocessor reads the updated number of pulses and generates an updated frequency value based on the updated number of pulses and the predetermined frequency of the reference signal.
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申请公布号 |
US5442278(A) |
申请公布日期 |
1995.08.15 |
申请号 |
US19930126329 |
申请日期 |
1993.09.24 |
申请人 |
ACER PERIPHERALS, INC. |
发明人 |
FAN CHIANG, YUNG F.;LEE, KUN-M. |
分类号 |
G01R23/10;(IPC1-7):G01R23/02 |
主分类号 |
G01R23/10 |
代理机构 |
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地址 |
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