Method and apparatus for subperiod measurement of successive variable time periods

Claim 3

A self-clocking network for detecting a subperiod of each period of successive time periods whose durations may vary over a wide range comprising: timing means responsive to the start and stop of each one of the successive time periods to generate a discrete signal representative of the duration of each one of the successive time periods; storage means for storing the discrete duration representative signal generated during each time period while the timing means is generating another discrete signal representative of the duration of the immediately successive time period; means responsive to the discrete signal stored during each time period to provide a discrete reference signal representative of a particular segment of a selected percentage of the duration represented by the stored signal; and comparator means for receiving the discrete signal being generated by the timing means and the discrete reference signal to provide a responsive indication when the signal being generated by the timing means represents a time within the particular selected percentage segment of the duration represented by the discrete reference signal.

Claim 4

A self-clocking network for detecting a subperiod of each period of successive time periods whose durations may vary over a wide range comprising: timing means responsive to the start and stop of each one of the successive time periods to generate a discrete signal representative of the duration of each one of the successive time periods; storage means for storing the discrete duration representative signal generated during each time period while the timing means is generating another discrete signal representative of the duration of the immediately successive time period; means responsive to the discrete signal stored during each time period to provide a discrete reference signal representative of a particular segment of a selected percentage of the duration represented by the stored signal; and comparator means for receiving the discrete signal being generated by the timing means and the discrete reference signal to provide a responsive indication when the signal being generated by the timing means represents a time within the particular selected percentage segment of the duration represented by the discrete reference signal.

Claim 5

The network according to claim 2 further comprising means responsive to the stored discrete duration representative signal for controlling the timing means to issue duration representative signals whose absolute magnitude stored for initiating the generation of the reference signal is not greater than a predetermined absolute magnitude regardless of changes in the duration of successive time periods.

Claim 6

The network according to claim 2 wherein successive pulses indicate the start and stop of the successive time periods, the timing means is a ramp signal generating means for generating successive ramp signals in response to successive pulses, each ramp signal having a final level from which the duration of the time period during which the ramp Signal was generated can be determined, the storage means stores a discrete signal representative of the final level of the ramp signal generated during each time period, and the discrete reference signal provided by the reference signal generating means represents a particular level segment of a selected percentage of the final level of the generated ramp signal.

Claim 7

The network according to claim 4 wherein the discrete reference signal provided by the reference signal generating means represents a particular level less than the final level of the ramp signal, and the comparator means provides the responsive indication when the ramp signal being generated by the timing means reaches a level corresponding to the particular level represented by the discrete reference signal.

Claim 8

The network according to claim 4 further comprising means responsive to the stored discrete signal for controlling the ramp signal generating means to change the slope of the ramp signal generated thereby to maintain the final level of each ramp signal constant regardless of changes in the duration between successive pulses.

Claim 9

The network according to claim 4 wherein the reference signal generating means provides a discrete reference signal representative of a first particular level and of a second particular greater level of the ramp signal, and the comparator means provides a first indication when the ramp signal being generated by the timing means reaches a level corresponding to the first particular level and a second indication when the ramp signal reaches a level corresponding to the second particular level.

Claim 10

The network according to claim 7 further comprising means responsive to the stored discrete signal for controlling the ramp signal generating means to change the slope of the ramp signal generated thereby to maintain the final level of each ramp signal constant regardless of changes in the duration between successive pulses.

Claim 11

The network according to claim 2 wherein the timing means includes a switching means and a charging means, the storage means is a charge holding means, the charging means is responsive to the switching means to initiate at the start of each time period charging for the duration of each time period, the charge holding means is responsive to the switching means at the stop of each time period to hold charge indicative of the maximum level of the charge of the charging means during the preceding time period, the held charge representative of the duration of the preceding time period, the reference signal generating means is a voltage divider means providing a voltage reference signal representative of the particular segment of the duration represented by the held charge, and the comparator means provides the responsive indication when the charge of the charging means is within the segment represented by the voltage reference signal.

Claim 12

The network according to claim 9 wherein successive pulses indicate the start and stop of the successive time periods, the charging means and charge holding means each includes one of a pair of capacitors each extending to a current generator source through the switching means, the switching means responds to successive pulses to couple the current source to one of the capacitors during alternate time periods and to the other of the capacitors during the remaining time periods whereby each of the capacitors alternately serves as the charging means and as the charge holding means, and further comprising means for coupling the capacitors serving as the charge holding means to the voltage divider means for the duration of the time period said capacitor serves as the charge holding means.

Claim 13

The network according to claim 10 further comprising a second switching means extending across each of said capacitors, the second switching means responding to successive pulses and momentarily shorting the capacitor serving as the charge holding means to discharge the held charge prior to charging the capacitor during the succeedIng time period.

Claim 14

The network according to claim 11 further comprising means responsive to the level of charge held by the charge holding capacitor for controlling the current generator source to change the level of held charge provided during each time period constant regardless of changes in the duration between successive pulses.

Claim 15

The network according to claim 9 wherein the voltage divider means provides a first voltage representative of a first particular level of charge and a second voltage representative of a particular second greater level of charge, and the comparator means includes a pair of comparators, each of the comparators referenced to the charge on the charging means, and one of the comparators coupled to receive the first voltage and the other of the comparators coupled to receive the second voltage provided by the voltage divider means whereby the one comparator provides a first indication when the level of the charge on the charging means reaches that corresponding to the first voltage and the other comparator means provides a second indication when the level of the charge on the charging means reaches that corresponding to the second voltage.

Claim 16

The network according to claim 13 further comprising means responsive to the level of charge held by the charge holding means for controlling the rate of charge of the charging means to maintain the level of held charge provided during each time period constant regardless of changes in the duration of successive time periods.

Claim 17

The network according to claim 14 further comprising a second switching means responsive to the start of each successive time period to discharge the charge holding means prior to initiating the charge of the charging means during the succeeding time period.