Herschel receiver
Herschel receiver | |||||||||
View static image | |||||||||
Pattern type | Conduit | ||||||||
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Input | tandem glider | ||||||||
Output | R-pentomino | ||||||||
Number of cells | 48 | ||||||||
Bounding box | 46 × 32 | ||||||||
Step | Unknown | ||||||||
Recovery time (ignoring FNG if any) |
117 ticks | ||||||||
Minimum overclock period (ignoring FNG if any) |
Unknown | ||||||||
Spartan? | Yes | ||||||||
Discovered by | Paul Callahan | ||||||||
Year of discovery | 1996 | ||||||||
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Herschel receiver, in the narrow sense, is a converter found by Paul Callahan in 1996 as part of the first stable glider reflector. An input glider hitting a bait block triggers a pi-heptomino reaction, which with other Spartan catalysts yields an output R-pentomino and restores the block. In the broad sense, the term Herschel receiver can also refer to other tandem glider-to-Herschel converters, such as G4 receiver.
In the infobox, the succeeding conduits RF28B and BFx59H convert the R-pentomino to a Herschel; alternatively a single loaf as RF48H can be used.
Details
If the leftmost wing-eating block is replaced with an eater 1 in the ghost position, an optional output glider will emerge heading opposite direction from input. The bait block and two eaters also appear in glider stopper, boojum reflector and rectifier which release the same 180-degree glider. These mechanisms differ by subsequent catalyst-induced outcome: the former gives a 0-degree glider rather than R-pentomino, and the latter two are purely 180-degree reflectors without any other output.
The process produces an extra beehive as well, leaving an obstacle on the input lane; it can be removed with a second input glider, either parallel to the first input or perpendicular to it. The term "Herschel receiver" originates from the first case, where the pattern takes a tandem glider (with lane separations of -2, 2, 5, or 6 half-diagonals, labelled G2, G5 or G6 respectively) as an input. In particular, the G5 glider pair from Callahan's 1997 Herschel transmitter is compatible with this receiver; this pair is shown in the infobox, with the first glider destroying the beehive beforehand and the second triggering the mechanism and leaving the beehive.
When the beehive is to be deleted with a perpendicular glider instead, the glider may come from downstream Herschel conduits. This way the deletion happens after receiving a signal, and the time gap between these two events determines the repeat time of the resulting device. For example, in the very first stable reflector or glider-to-Herschel converter constructed on October 15, 1996, a long chain was appended that consisted of RF28B, BFx59H, seven R64 and seven L156 alternating, another L156, twelve F117 and finally Fx119 in series, leading to a whopping 4840-tick repeat time. Over the years many designs has been made to reduce the repeat time; most recently, in 2012 Sergey Petrov (Guam) used a new RF48H and the FNG-reflecting mechanism as in 487-tick reflector for quick junk cleanup, achieving 444 ticks.[1] Not considering convenience for glider construction, all of these Herschel-receiver-based technologies have now been surpassed by cleaner and consequently much faster syringe-based ones.
Variant
In 2015, Michael Simkin found a Spartan variant of Herschel receiver, as shown below.[2] The wing-eating block is replaced with a transparent loaf and two eater 1s, shifting the residual beehive by (-6, -5). This version accepts a tandem glider labelled G6 or G13 as an input.
Herschel receiver variant (click above to open LifeViewer) RLE: here Plaintext: here |
In the patterns shown above, ghost Herschels are used to mark output location.
See also
References
- ↑ Sergey Petrov (September 29, 2012). Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
- ↑ Michael Simkin (May 1, 2015). Re: The Hunting of the New Herschel Conduits (discussion thread) at the ConwayLife.com forums
External links
- Herschel receiver at the Life Lexicon
- Stephen Silver on Stable Reflectors at Paul Callahan's Page of Conway's Life Miscellany
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