Boots – shoes – and leggings
Patent
1980-03-07
1983-05-10
Krass, Errol A.
Boots, shoes, and leggings
324166, 364484, 377 20, 377 47, G01P 348
Patent
active
043833039
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to an apparatus and method for converting one frequency signal to another frequency signal and, more particularly, to a frequency conversion apparatus and method for determining the speed of rotation of a rotating member.
2. Background Art
Digital frequency conversion circuits have a wide variety of applications. For example, one particular use is in converting frequencies to determine the speed of a vehicle engine. Typically, a frequency signal is generated by detecting teeth or other discontinuities on a rotating output shaft of the engine. Unless the shaft has a certain number of teeth, this frequency signal is then converted to another or output frequency signal which is used to measure engine speed.
More specifically, advantageously, the rotating shaft will have such a certain number of teeth, i.e., 60 or a multiple thereof. The frequency signal generated by detecting these teeth can then be counted for one second and this count will then be numerically equal to the RPM of the engine. This procedure is simple due to the wide availability of counters having a time base of one second which can be used to count the pulses of the frequency signal.
However, not uncommonly, the rotating shaft has a number of teeth other than 60 or a multiple thereof. Consequently, the engine speed cannot be determined directly by counting with a counter having a one second time base. Therefore, frequency conversion apparatus are employed in which the frequency signal obtained by detecting the teeth on the shaft is converted to an output signal having a frequency as if the shaft had 60 teeth. The pulses of this output frequency signal can then be counted with a counter having a one second time base to determine the engine speed.
Usually, frequency conversion apparatus for determining the speed of rotation of a rotating member having teeth other than 60 or a multiple thereof will convert signals from the frequency domain to the time domain and back to the frequency domain. For example, in one prior frequency conversion apparatus the frequency signal obtained by sensing teeth on the rotating shaft is used to set a time period during which pulses from a fixed oscillator are counted. This time period can be, for example, the time it takes two consecutive teeth on the rotating member to be sensed.
A disadvantage with the prior frequency conversion apparatus is that it requires a relatively large number of electronic components because of the change between the frequency and time domains. This larger number of components results in an apparatus which is less economical and reliable, and one which requires more electrical power and occupies more space, at least in relation to the present invention.
Also, the prior frequency conversion apparatus can follow fast rates of change in the speed of rotation of the shaft, but not without a disadvantage given below. This is accomplished by the fact that the time period for counting the oscillator pulses changes as the shaft rotation speed changes. For example, as the shaft speed increases, the time period will decrease due to the increased speed at which the two consecutive teeth are sensed. Since pulses from the fixed oscillator are being counted, and since the variation in time periods occurs in a stepwise manner, the converted frequency will be disadvantageously a step function of the input frequency. In other words, the converted frequency will not follow smoothly changes in the input frequency.
Two reasons for not wanting this step function are as follows. In some applications of the frequency conversion circuit, a frequency to DC (F/DC) converter will convert the output frequency of the former to a DC voltage to drive, for example, a chart recorder to provide a trace of the voltage. However, the output voltage of the F/DC converter, and hence the trace, will be a step function when, preferably, it should be smooth since the rotational speed of the shaft may be changing smoothly. Also, it may be desirable to analyze the frequency s
REFERENCES:
patent: 3836758 (1974-09-01), Schneider et al.
patent: 3845396 (1974-10-01), Rutman
patent: 3882303 (1975-05-01), Linder
patent: 3930199 (1975-12-01), Valis
patent: 3963987 (1976-06-01), Rivere
patent: 3982199 (1976-09-01), Green
patent: 4074196 (1978-02-01), Webster
patent: 4167699 (1979-09-01), Baker
IBM Tech. Discl. Bulletin; vol. 13, No. 4, Sep. 1970; Armonk, N.Y.; Bederman; "Computer and Apparatus for Measuring Rotational Speed"; pp. 1017-1018.
Caterpillar Tractor Co.
Fliesler Martin C.
Krass Errol A.
LandOfFree
Frequency signal conversion apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Frequency signal conversion apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Frequency signal conversion apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-528879