Multiple FM dither
View Patent ↗Multiple noise-FM dither. An analog dither signal is generated by summing two or more noise-FM signals, each noise-FM signal being a carrier modulated by a noise source.
1. A dither signal generator comprising:
a plurality of noise-FM sources, each noise-FM source comprising a carrier generator which is frequency modulated by an independent noise source, and
a summing node summing the plurality of noise-FM sources to produce a dither.
2. The dither signal generator of claim 1 where each noise-FM source produces a digital signal.
3. The dither signal generator of claim 2 where the digital noise-FM signals are summed and further converted to an analog dither signal.
4. The dither signal generator of claim 1 where each noise-FM source produces an analog signal.
5. The dither signal generator of claim 4 where the analog noise-FM signals are summed to produce an analog dither signal.
6. The dither signal generator of claim 1 where two noise-FM sources are used.
7. The dither signal generator of claim 1 where more than two noise-FM sources are used.
8. A method of generating a dither signal comprising:
generating a plurality of noise-FM signals, each noise-FM signal produced by frequency modulating a carrier with a noise signal, and
summing the noise-FM signals to produce a dither signal.
9. The method of claim 8 where the noise-FM signals are generated and summed digitally, then converted to analog to produce an analog dither signal.
10. The method of claim 8 where each noise-FM signal is an analog signal.
11. The method of claim 8 where the noise signals are generated digitally and converted to analog signals used to frequency modulate the carrier.
12. The method of claim 8 where the noise signals are generated in analog form.
13. The method of claim 8 where two noise-FM signals are used.
14. The method of claim 8 where more than two noise-FM signals are used.
15. A dither signal generator comprising:
a plurality of noise-FM sources, each noise-FM source comprising a carrier generator which is frequency modulated by an independent noise source and a noise generator feeding a noise shaping and scaling filter; and
a summing node summing the plurality of noise-FM sources to produce a dither.
16. The dither signal generator of claim 15 where the noise source and shaping and scaling filter produces a signal having a bandlimited Gaussian amplitude distribution.
17. A method of generating a dither signal comprising:
generating a plurality of noise-FM signals, each noise-FM signal produced by frequency modulating a carrier with a noise signal, and
summing the noise-FM signals to produce a dither signal, wherein the noise signal has a Gaussian amplitude distribution.
18. The method of claim 17 where the noise signal has a bandlimited Gaussian amplitude distribution.