 Method and apparatus for calibrating a display using an array of cameras |
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| Dual disc adapter with downward sloping outside corner wedges |
| The inventors have found that these two diverse sets of needs can be met by a single adapter insert ... |
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| Digital data storage assembly with particular hub adaptor |
| OF THE INVENTION Referring now to FIG. 1 of the drawing figures, there is shown an exploded ... |
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| CMOS to ECL output buffer |
| FIG. 1 illustrates an overall view of a circuit which includes conversion of CMOS voltage levels ... |
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| Processing system with delta-based video data encoding |
| The present invention involves apparatus and methods for providing video, audio, graphics, input/... |
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| Folded bag handle |
| I claim: 1. A handle-equipped bag comprising a carrying handle formed from a sheet of folded ... |
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| Method and apparatus for determining AM modulation factor |
| OF THE INVENTION As shown in FIG. 1, an AM signal (which is referenced to ground, as it will be ... |
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| Sampled differential analyzer |
| OF THE PREFERRED EMBODIMENTS FIG. 1 is a functional block diagram of the analyzer. The image ... |
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Signal generator
| Details |
Inventors: Kimber, Ian D.; Young, Nicholas A.;
Assignee: EMI Limited (Hayes, GB)
Primary Examiner: Safourek; Benedict V.
Assistant Examiner: Chin; Stephen
Attorney, Agent or Firm: Fleit, Jacobson, Cohn, Price, Holman & Stern
A signal generator produces a spread-spectrum bandwidth signal in the frequency range 40 to 90 KHz for use in a domestic mains signalling system. In the generator, sixteen individual frequencies, equi-spaced in that range, pass to samplers operating at a clock frequency of 204.8 KHz and then to quantizers before storage. The resultant signals are then assembled in appropriate manner by selector switch before being filtered when (temporarily) in the frequency domain. The resultant signals duly reach catalogue store, whose output can be used for programming an EPROM in a mains signalling interface unit. |
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DETAILED DESCRIPTION The present invention provides a signal generator for producing a spread-spectrum bandwidth signal ranged between specified frequencies, the generator having: means to produce a number of single-frequency signal waveforms, each having a distinctive frequency within the range of specified frequencies; means to sample each of the single-frequency signal waveforms at a sampling rate exceeding the frequency of that waveform; means to quantise, between two or more levels, the sampling values of each waveform; and means to combine together the quantised sampling values for a plurality of the waveforms in a predetermined fashion.
In one form of the invention, the combination means assembles the quantised sampling values attributed to the waveforms in order of ascending frequency of waveform.
Alternatively, the values could be assembled in descending frequency of waveform, or in random manner independent of frequency, or in any suitable combination of these modes.
Preferably, the generator includes means to ensure phase continuity between quantised sampling values of separate waveforms upon joining at the combination means.
This may incorporate, for example, storage means for holding sequences of values for the waveforms (or sequences of waveform portions themselves), whereby all the sequences have a common starting-point in phase; thus, by ensuring that, in the combination operation, all the sequences terminate at that same phase position, then phase-continuity will be achieved.
Preferably, the waveform-production means has a frequency distribution arranged to exclude waveforms at or closely adjacent one or more frequencies associated with common forms of interference.
By "closely adjacent", there is meant that all the waveforms from the production means are sufficiently spaced from the frequency or frequencies associated with interference such that there is substantially no combination (or overlap) of waveforms at the interference frequency or frequencies.
In this way, the effect of any such interference signals on the generated spectrum is minimised
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Television 
