Frequency Modulation - Revision history

Jnc: +cat

2018-12-14T19:21:13Z

+cat

Jnc: Proper cat

2018-10-18T19:54:21Z

Proper cat

Jnc: Slightly clarify

2017-10-25T15:34:10Z

Slightly clarify

Jnc: An OK start

2017-10-25T14:42:08Z

An OK start

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'''Frequency Modulation''' (or '''FM''') is an encoding technique, used in [[magnetic storage]] such as [[disk]]s and [[Disk#Low-cost disks|floppy drive]]s.

In FM there is a reversal (signal level, or magnetic flux) at the start of every data bit time; for a '1', there is an additional reversal in the middle of the bit time, with no reversal indicating a '0'.

Consecutive zeros show a reversal between data bit times; consecutive ones show two reversals in every bit time (i.e. doubling the frequency of reversals; hence the name).

It was mostly replaced by [[Modified Frequency Modulation]], which can store twice as many bits in the same maximum reversal rate.

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	It was mostly replaced by [[Modified Frequency Modulation]], which can store twice as many bits in the same maximum reversal rate.		It was mostly replaced by [[Modified Frequency Modulation]], which can store twice as many bits in the same maximum reversal rate.

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 '''Frequency Modulation''' (or '''FM''') is an encoding technique, used in [[magnetic storage]] such as [[disk]]s and [[Disk#Low-cost disks|floppy drive]]s.
-In FM there is a reversal (signal level, or magnetic flux) at the start of every data bit time; for a '1', there is an additional reversal in the middle of the bit time, with no reversal indicating a '0'.
+In FM there is a reversal (signal level, or magnetic flux) at the start of every data bit time (i.e. every clock time); for a '1', there is an additional reversal in the middle of the bit time, with no reversal indicating a '0'.
 Consecutive zeros show a reversal between data bit times; consecutive ones show two reversals in every bit time (i.e. doubling the frequency of reversals; hence the name).