Variable speed facsimile transmitter using storage mode photodetection array

Claim 1

A variable speed facsimile transmitter including means for generating synchronization pulses at one of a plurality of manually selectable rates, a storage mode photodetection array and means for driving said photodetection array in response to each of said sync pulses, comprising means for discharging said photodetection array at an instant delayed from the time of occurrence of the sync pulse by an interval in dependence on the difference between the selected synchronization rate and the highest one of the sync rates so that said photodetection array is allowed to develop charges during a constant interval regardless of the sync rate so selected.

Claim 8

A method for operating a variable speed facsimile transmitter having a plurality of selectable line scanning frequencies to provide different transmission speeds and a storage mode photodetection array adapted to generate a video line signal, comprising the steps of: (a) generating sync pulses at a frequency corresponding to a selected one of said scanning frequencies; (b) determining the difference between the period of the selected frequency and the period of the highest one of said scanning frequencies; (c) causing said photodetection array to discharge its stored electrical energy at an instant delayed from the time of occurrence of the sync pulse by an interval determined by said difference in period of said scanning frequencies when the selected frequency is other than said highest frequency; (d) allowing said photodetection array to charge electrical energy in response to the end of said time interval when the selected frequency is other than said highest frequency, or allowing said photodetection array to charge electrical energy in response to said sync pulse when said highest frequency is selected; and (e) driving said photodetection array to generate said video line signal in response to each of said sync pulses.

Claim 9

A method for operating a variable speed facsimile transmitter having a plurality of selectable line scanning frequencies to provide different transmission speeds and a storage mode photodetection array adapted to generate a video line signal, comprising the steps of: (a) generating sync pulses at a frequency corresponding to a selected one of said scanning frequencies; (b) determining the difference between the period of the selected frequency and the period of the highest one of said scanning frequencies; (c) causing said photodetection array to discharge its stored electrical energy at an instant delayed from the time of occurrence of the sync pulse by an interval determined by said difference in period of said scanning frequencies when the selected frequency is other than said highest frequency; (d) allowing said photodetection array to charge electrical energy in response to the end of said time interval when the selected frequency is other than said highest frequency, or allowing said photodetection array to charge electrical energy in response to said sync pulse when said highest frequency is selected; and (e) driving said photodetection array to generate said video line signal in response to each of said sync pulses.

Claim 13

A method of operating a variable speed facsimile transmitter having a storage mode photodetection array and means for driving said array at one of a plurality of selectable line scanning frequencies F 1 , F 2 , . . . F n where F n is the highest frequency, comprising: dividing a time interval T L which corresponds to the reciprocal of said highest frequency F n into (M+N) equal time segments, where M is an integer inclusive of zero and N is an integer exclusive of zero; multiplying said interval T L by N/(M+N) to derive a minimum time interval T min necessary to obtain a video signal of an acceptable signal level; dividing a time interval T i which corresponds to the reciprocal of a selected line scanning frequency into a first section in which said photodetection array is prevented from deriving said video signal and a second section equal to said minimum time interval T min ; determining the first section by counting a unit time interval equal to a common multiple of said scanning frequencies a number of times equal to ##STR1## where F cm is said common multiple, and F i is the selected frequency; and allowing said photodetection array to develop charges during said minimum time interval T min to derive said video signal at the end of said minimum time interval.

Claim 14

A method of operating a variable speed facsimile transmitter having a storage mode photodetection array and means for driving said array at one of a plurality of selectable line scanning frequencies F 1 , F 2 , . . . F n where F n is the highest frequency, comprising: dividing a time interval T L which corresponds to the reciprocal of said highest frequency F n into (M+N) equal time segments, where M is an integer inclusive of zero and N is an integer exclusive of zero; multiplying said interval T L by N/(M+N) to derive a minimum time interval T min necessary to obtain a video signal of an acceptable signal level; dividing a time interval T i which corresponds to the reciprocal of a selected line scanning frequency into a first section in which said photodetection array is prevented from deriving said video signal and a second section equal to said minimum time interval T min ; determining the first section by counting a unit time interval equal to a common multiple of said scanning frequencies a number of times equal to ##STR1## where F cm is said common multiple, and F i is the selected frequency; and allowing said photodetection array to develop charges during said minimum time interval T min to derive said video signal at the end of said minimum time interval.