Claims
- 1. Apparatus for providing an analogue output which is a trigonometrical function of the sum of an analogue angle amplitude modulated input represented by a sin 2.pi. ft cos .theta. and a sin 2.pi. ft sin .theta., and a digital angle input .phi., comprising a digital processor for producing said digital angle input .phi. comprising digital words representing the value of sin .phi. and cos .phi., said processor having a capability to modify said digital words to compensate for errors in said analogue input, said analogue input containing errors expressed as (1+.epsilon..sub.1) sin (.theta.+.SIGMA..sub.1) and (1+.epsilon..sub.2) cos (.theta.+.SIGMA..sub.2), said processor modifying the value represented by said digital words using the following digital input functions: ##EQU2## two digital/analogue converters for multiplying sines and cosines of the two angles to produce signals --a sin 2.pi. ft cos .theta. sin .phi. and --a sin 2.pi. ft sin .theta. cos .phi., and means for combining signals produced by said converters whereby a signal a sin 2.pi. ft sin (.theta.+.phi.) is produced.
- 2. Apparatus as claimed in claim 1 wherein said combining means comprises an operational amplifier for adding signals from the converters.
- 3. Apparatus as claimed in claim 1 further comprising a resolver to produce, when set at angle .theta., analogue signals representing sin .theta. and cos .theta..
- 4. Apparatus as claimed in claim 1, wherein said produced digital words are in offset binary form.
- 5. Apparatus as claimed in claim 1, wherein said produced digital words have at least 12 bits each.
Parent Case Info
This is a continuation of application Ser. No. 41,438 filed May 22, 1979, abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1354350 |
May 1974 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
41438 |
May 1979 |
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