Abstract A system for synchronising a rotary member with a series of synchronising pulses, suitable for use in synchronising a film projector with a television scanning raster comprises a rotary member; a divider for obtaining two repetitive signals whose frequency is relatively small from a series of synchronising pulses fed to the said divider; a generator for providing in response to a first of the repetitive signals a repetitive sawtooth wave form of the same fundamental frequency as the first repetitive signal; a synchro-resolver having a stator arranged to be energised by a polyphase signal derived from the second of the two repetitive signals, and a rotor arranged to be driven in accord with the movement of the rotary member; a further generator responsive to the output of the synchro-resolver to provide a series of sampling pulses at a frequency proportional to the output of the synchro-resolver; and a comparator for comparing the phase of the sampling pulses with that of the repetitive sawtooth wave form so as to provide a control signal for operating the rotary member.
Inventors
👤 J Millward
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-26 20:51
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/36
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
152 words
A synchronising system comprising a rotary member; divider means to which is fed a series of synchronising pulses for obtaining from the said series two repetitive signals whose frequency difference is relatively small; means for providing in response to a first of the two repetitive signals a repetitive sawtooth waveform of the same fundamental frequency as the first repetitive signal; a synchro-resolver including a stator arranged to be energised by a polyphase signal derived from the second of the two repetitive signals, and a rotor arranged to be driven in accord with the movement of the rotary member; means responsive to the output of the synchro-resolver to provide a series of sampling pulses at a frequency proportional to the output of the synchro-resolver; and means for comparing the phase of the sampling pulses with that of the repetitive sawtooth waveform so as to provide a control signal for operating the rotary member.
Claim 2
Dependent Claim
152 words
A synchronising system comprising a rotary member; divider means to which is fed a series of synchronising pulses for obtaining from the said series two repetitive signals whose frequency difference is relatively small; means for providing in response to a first of the two repetitive signals a repetitive sawtooth waveform of the same fundamental frequency as the first repetitive signal; a synchro-resolver including a stator arranged to be energised by a polyphase signal derived from the second of the two repetitive signals, and a rotor arranged to be driven in accord with the movement of the rotary member; means responsive to the output of the synchro-resolver to provide a series of sampling pulses at a frequency proportional to the output of the synchro-resolver; and means for comparing the phase of the sampling pulses with that of the repetitive sawtooth waveform so as to provide a control signal for operating the rotary member.
Claim 3
Dependent Claim
37 words
A synchronising system as claimed in claim 1, wherein the means responsive to the output of the synchro-resolver is arranged to provide a series of sampling pulses at a frequency equal to the output of the synchro-resolver.
Claim 4
Dependent Claim
34 words
A synchronising system as claimed in claim 1, wherein the rotary member is arranged to commence rotation when the phase difference between the sampling pulses and the sawtooth waveform is a non-zero predetermined value.