Title:
DEMODULATOR
Document Type and Number:
Japanese Patent JP3232834
Kind Code:
B2
Abstract:
PURPOSE: To improve the data read rate by switching a pulse frequency received by a counter with an external control input so as to switch the discrimination coefficient of the demodulator.
CONSTITUTION: A variable frequency divider 9 being a 2nd frequency divider applies 1/n (n is a natural number) to an output pulse of a pulse oscillator 1. Various frequency division ratios are selected by an external control input terminal (s) (n is variable in a range of 1/2m<n<m). A second counter 5 down counters the output of the divider 9. Since the frequency of the pulse signal given to the counter 5 is made variable by the frequency divider 9 in this way, the pulse width of a discrimination signal (e), that is, a discrimination coefficient n/m is selected by the external control input terminal (s). Thus, a read rate of data is enhanced by adjusting the discrimination coefficient n/m for a card whose data are hardly read because of locally different recording frequencies and reading the data again.
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Inventors:
Hiroyuki Ueda
Application Number:
JP31491793A
Publication Date:
November 26, 2001
Filing Date:
December 15, 1993
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
G11B20/14; H03M5/06; (IPC1-7): H03M5/06; G11B20/14
Domestic Patent References:
| JP6012839A | ||||
| JP51114912A | ||||
| JP51115808A | ||||
| JP6021658A | ||||
| JP6150258A | ||||
| JP62149225A | ||||
| JP6386921A | ||||
| JP273724A |
Attorney, Agent or Firm:
Fumio Iwahashi (2 others)