EP 0914716 A2 19990512 - FREQUENCY SYNTHESIZER, PARTICULARLY FOR USE IN A CHANNEL IC FOR HARD DISKS
Title (en)
FREQUENCY SYNTHESIZER, PARTICULARLY FOR USE IN A CHANNEL IC FOR HARD DISKS
Title (de)
FREQUENZSYTHETISIERER INBESONDERE ZUR VERWENDUNG IN EINER KANALSCHALTUNG FÜR FESTPLATTEN
Title (fr)
SYNTHETISEUR DE FREQUENCES UTILISE EN PARTICULIER DANS UN CIRCUIT CANAL POUR DISQUE DUR
Publication
Application
Priority
- EP 98905549 A 19980312
- EP 97201221 A 19970424
- IB 9800327 W 19980312
Abstract (en)
[origin: WO9848514A2] In a channel IC for a hard disk it is desirable that the write oscillator, but preferably also the read oscillator and the equalizer, can rapidly change their frequencies upon a change of zone on the hard disk while the stability and accuracy are maintained. The phase-locked loops in which such oscillators are included inherently respond slowly to a new frequency setting. According to the invention a rapid change in frequency is obtained, while the accuracy and stability are retained, in that by means of an analog multiplier/divider a substantial part of the control signal necessary to set the oscillators to a new frequency is derived from a control signal available in a second PLL loop, preferably the PLL loop of the servo circuit for controlling the read/write heads. The PLL loop of the write oscillator now merely has to provide the fine control.
IPC 1-7
IPC 8 full level
G11B 20/14 (2006.01); H03L 7/07 (2006.01); H03L 7/23 (2006.01); G11B 20/12 (2006.01)
CPC (source: EP)
G11B 20/1403 (2013.01); H03L 7/07 (2013.01); H03L 7/0805 (2013.01); H03L 7/23 (2013.01); G11B 20/1258 (2013.01)
Citation (search report)
See references of WO 9848514A2
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
WO 9848514 A2 19981029; WO 9848514 A3 19990128; EP 0914716 A2 19990512
DOCDB simple family (application)
IB 9800327 W 19980312; EP 98905549 A 19980312