Apparatus for measuring the speed of a moving member

Claim 2

Apparatus for measuring the speed of a moving member, comprising: means for producing a sensor signal which periodically rises above and falls below a reference level at a frequency proportional to the speed of the moving member; means for producing a first bilevel signal which rises to an upper level as the sensor signal rises above the reference level and which falls to a lower level as the sensor signal falls below the reference level and for producing a second bilevel signal which rises to an upper level as the sensor signal falls below the reference level and which falls to a lower level as the sensor signal rises above the reference level, the means including at least a pair of junction transistors through which the first and second bilevel signals are respectively derived for appreciably delaying either the rise or the fall of the first and second bilevel signals due to the minority carrier storage effect in at least the pair of transistors such that the first and second bilevel signals overlap during respective transitions between the upper and lower levels; means for producing successive trigger pulses each developed in response to the overlap of the first and second bilevel signals during successive transitions between the upper and lower levels such that the frequency of the trigger pulses is twice the frequency of the sensor signal; means for producing successive incremental pulses each having a constant amplitude and a constant width and each developed in response to a different one of the trigger pulses; and means for integrating the successive incremental pulses to produce an analog signal which is substantially constant at a level proportional to the speed of the moving member.

Claim 3

Apparatus for measuring the speed of a moving member, comprising: means responsive to the motion of the moving member for producing a sensor signal which pEriodically rises above and falls below a reference level at a frequency porportional to the speed of the moving member; means responsive to the sensor signal and to the reference level for producing a first bilevel signal which rises to an upper level when the sensor signal rises above the reference level and which falls to a lower level when the sensor signal falls below the reference level and for producing a second bilevel signal which rises to an upper level when the sensor signal falls below the reference level and which falls to a lower level when the sensor signal rises above the reference level, the means including at least a pair of junction transistors through which the first and second bilevel signals are respectively derived for appreciably delaying either the rise or the fall of the first and second bilevel signals due to the minority carrier storage effect in at least the pair of transistors such that during respective transitions between the upper and lower levels the first and second bilevel signals are either both above or both below a threshold level defined between the upper and lower levels; means responsive to the first and second bilevel signals and responsive to the threshold level for producing successive trigger pulses each developed when the first and second bilevel signals are either both above or both below the threshold level such that the frequency of the trigger pulses is twice the frequency of the sensor signal; means responsive to the trigger pulses for producing successive incremental pulses each having a constant amplitude and a constant width and each developed in response to a different one of the incremental pulses for producing an analog signal by integrating the incremental pulses such that the analog signal is substantially constant at a level proportional to the speed of the moving member.

Claim 4

Apparatus for measuring the speed of a moving member, comprising: means responsive to the motion of the moving member for producing a sensor signal which pEriodically rises above and falls below a reference level at a frequency porportional to the speed of the moving member; means responsive to the sensor signal and to the reference level for producing a first bilevel signal which rises to an upper level when the sensor signal rises above the reference level and which falls to a lower level when the sensor signal falls below the reference level and for producing a second bilevel signal which rises to an upper level when the sensor signal falls below the reference level and which falls to a lower level when the sensor signal rises above the reference level, the means including at least a pair of junction transistors through which the first and second bilevel signals are respectively derived for appreciably delaying either the rise or the fall of the first and second bilevel signals due to the minority carrier storage effect in at least the pair of transistors such that during respective transitions between the upper and lower levels the first and second bilevel signals are either both above or both below a threshold level defined between the upper and lower levels; means responsive to the first and second bilevel signals and responsive to the threshold level for producing successive trigger pulses each developed when the first and second bilevel signals are either both above or both below the threshold level such that the frequency of the trigger pulses is twice the frequency of the sensor signal; means responsive to the trigger pulses for producing successive incremental pulses each having a constant amplitude and a constant width and each developed in response to a different one of the incremental pulses for producing an analog signal by integrating the incremental pulses such that the analog signal is substantially constant at a level proportional to the speed of the moving member.