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Contents of journal 118 June 2022
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- CREG Journal 118 (0-24)
(PDF 6.2MB) Individual articles may be available below
- This issue has a cover date of June 2022 and was published on 8 June 2022.
Corrections: In 'The Circle of Least Confusion' in the appendix, on page 17, "j117" should read "j118". Also, equation 1 on page 17 is incorrect, although the rest of the equations are OK. The equation is corrected in the online appendix (see below). In 'Position Encoder Uses Single-Track Gray Code: Part 2 ', appendix 2 on page 22 contains some errors. A corrected version will be uploaded here in October 2022. -
- Front Cover (1)
(PDF 1.8MB)
- Rob Gill observing fluorescence whilst setting up to photograph phosphorescence in KMC Valley Entrance during the recent CREG Field Meeting. Image: Chris Hunter
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- Contents (2)
(PDF 371KB)
- List of contents and masthead information.
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- News and Notes (2) For download see previous item
- Proposed Autumn 2022 Field Meeting, Getting Involved, Rob Gill.
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- The Pease Ultraphone - an SWT for Extreme Conditions (3-7)
(PDF 1.4MB)
- Brian Pease describes his design for this new single-wire telephone, which was designed for very long-range operation, even in levels of high noise when the line is not in good condition.
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- We Hear (8)
(PDF 409KB)
- Roundup of news and events: Mike Bedford brings us the latest to impact the world of cave radio and electronics. RMF-Owl: Drones to the Rescue, Introducing the Nicola 4, High Flying Rescue.
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- Spotlight on Luminescence: why Things Glow in the Dark (9-11)
(PDF 482KB)
- To support the recent interest in underground fluorescence and phosphorescence photography, Mike Bedford provides some simple background information about the physics behind these phenomena.
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- Letter to the Editor (12)
(PDF 272KB)
- Hunting Phosphorescence, Rob Gill; How Not to Lay a Telephone Cable, Chris Ross; Journal Back Issues, David Gibson.
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- Photographing Phosphorescence (13-15)
(PDF 515KB)
- Some minerals fluoresce when exposed to ultraviolet light. Some also phosphoresce, emitting light immediately following their exposure to UV. Rob Gill has been trying to photograph this transient phenomenon, using a Raspberry Pi-based sequencer, with both benchtop samples and with calcite formations in Yorkshire caves.
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- The Circle of Least Confusion (16-17)
(PDF 290KB)
- David Gibson describes a term in optics and photography that is used to derive the range of distances – the depth of field – over which a subject remains in good focus. This does not, of itself, require restating here, although there are some circumstances, such as the construction of stereoscopic and stacked-focus images, where a recap is useful. Additionally, there is a modification to the standard formula that extends its use to small-format digital cameras.
Corrections: please note that, in the paragraph headed Appendix, on page 17, "j117" should read "j118". Also, equation 1 on page 17 is incorrect, although the rest of the equations are OK. The equation is corrected in the online appendix (see below). -
- The Circle of Least Confusion: Appendix (A1-A2)
(PDF 250KB)
- This appendix to the article in CREGJ 118 by David Gibson provides the derivation of the Depth of Field formula and a further discussion on modifying the formula to deal with digital cameras with varying image formats. This document was revised and updated to version 4 on 5 October 2022.
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- Building Blocks (18)
(PDF 246KB)
- Minimising power consumption in processor-based circuits, by Tony Haigh.
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- Position Encoder Uses Single-Track Gray Code: Part 2 (19-22)
(PDF 382KB)
- There are many examples, in electronic equipment design, where it is necessary to measure a linear or rotary position, which is often achieved using an optical or magnetic encoder. Simple encoders only detect changes in relative position; multi-track encoders can measure absolute position but, as David Gibson explains, a single-track encoder can, under the right conditions, also encode absolute position. An online demonstration program accompanies this article at bcra.org.uk/cregj/more/j118. Corrections: Appendix 2 on page 22 contains some errors. A corrected version will be uploaded here in October 2022.
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- Cyclic Single-Track Gray Codes – Demo for CREGJ 118 (webpage)
- This online demonstration program by David Gibson accompanies the above article. Please note that this supplement is in preparation and will be available in October 2022, hopefully.
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- The Return of the CREG Field Meeting (23-24)
(PDF 1.6MB)
- After a hiatus of almost two years, as a result of the Covid pandemic, CREG got together for a field meeting at the end of May 2022. Interesting equipment was put through its paces, as Mike Bedford reports.
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undertaking charitable activities on behalf of the BCA.
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