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CGS Serge smooth and stepped generator (previous version) (view source)

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Revision as of 21:14, 28 December 2018 (view source) Rob Kam (talk \| contribs) (Created page with "thumb\|center\|800px\| '''CGSSSG''' the '''CGS Serge smooth stepped generator''' is a variation on the Classic Serge Smooth and Stepped Generato...")		Latest revision as of 18:26, 15 February 2023 (view source) InternetArchiveBot (talk \| contribs) (Rescuing 1 sources and tagging 0 as dead.) #IABot (v2.0.9.3)
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Line 6: == Description == [[File:cgs_photo_cgsssg_ssg2.jpg\|thumb\|right\|216px\|]] ''The Smooth & Stepped Function Generator (SSG) is s a complex multi-functional module to provide various slew and sample functions.<ref name="sc82">[http://www.carbon111.com/serge1982.pdf Serge Modular Music Systems catalog and data sheets, 1982]</ref>▼ ~~'''From the 1982 Serge catalog:'''~~ ''The ~~smooth~~Smooth section will place a positive and negative slew (glide) on a changing input voltage for lag effects, voltage controlled portamento, and non-linear, low frequency filtering. With the ~~cycle~~CYCLE jack patched to the input, the ~~unit~~Unit will oscillate yielding a voltage controlled triangle wave LFO. A high level into the ~~hold~~HOLD input will hold the current output level, whether the unit is oscillating or processing an external control voltage. This is identical to a track-and-hold function.''<ref name="sc82"/>▼ ▲''The Smooth & Stepped Function Generator (SSG) is s a complex multi-functional module to provide various slew and sample functions. ''The Stepped function can be used as a sample-and-hold with voltage controlled slew rate limiting. Slew rate limiting limits the size of the step at the output. With the step size limited to a small value, if the input is a random voltage, the output is a random voltage also, but it will only vary slightly from step to step, gradually covering the entire range of the input random voltage. No large changes in the output will be allowed. With the Cycle jack patched to the input and a trigger applied to the Sample input, complex staircase waveforms are generated.''<ref name="sc82"/>▼ ▲''The smooth section will place a positive and negative slew (glide) on a changing input voltage for lag effects, voltage controlled portamento, and non-linear, low frequency filtering. With the cycle jack patched to the input, the unit will oscillate yielding a voltage controlled triangle wave LFO. A high level into the hold input will hold the current output level, whether the unit is oscillating or processing an external control voltage. This is identical to a track-and-hold function.'' ''The coupler is an internal comparator comparing the Smooth and the Stepped outputs. This is useful for generating complex control voltages and for patching a random voltage generator.''<ref name="sc82"/>▼ ▲''The Stepped function can be used as a sample-and-hold with voltage controlled slew rate limiting. Slew rate limiting limits the size of the step at the output. With the step size limited to a small value, if the input is a random voltage, the output is a random voltage also, but it will only vary slightly from step to step, gradually covering the entire range of the input random voltage. No large changes in the output will be allowed. With the Cycle jack patched to the input and a trigger applied to the Sample input, complex staircase waveforms are generated.'' ▲''The coupler is an internal comparator comparing the Smooth and the Stepped outputs. This is useful for generating complex control voltages and for patching a random voltage generator.'' == A little on how it works == Line 97 ⟶ 95: For this module to work properly, a jumper must be installed between pad S and pad L. (This should have been installed during construction, although if you wish to test the two parts of the Stepped generator individually, it can be left disconnected until you have.) ''Patch the CYCLE output of the Smooth Function into the IN jack. Monitor the OUTPUT while turning the RATE knob full clockwise. The pitch should be about 100 Hz, and should go to sub-audio rates (as seen from the LED'S) when the knob is turned down. Check that a control voltage into the VC IN jack will control the rate. Note that this is an attenuating input only, with no inverting processing.''<ref name="ssg">[https://web.archive.org/web/20190429052140/http://www.serge.synth.net/documents/kit/ssg.html Smooth & Stepped Function Generator], kit instructions</ref>▼ ~~'''From Serge kit instructions:'''~~ ''A high level applied to the HOLD input (greater than about 4.5 volts) should stop the Smooth Function from cycling. With the Smooth Function patched to cycle, connect the CYCLE of the Smooth Function into the SAMPLE input of the Stepped Function. Patch the Stepped Function CYCLE to its IN jack. Using the STEPPED OUT to control the pitch of an oscillator, listen for the pitch change motion as the Stepped RATE is turned up. When fully clockwise, a triangular "staircase" waveform will be generated by the Stepped Function Generator. For best audible rate, the Smooth Function should be fairly slow. As the Stepped RATE knob is turned down, the staircase will slow down.''<ref name="ssg"/>▼ ▲''Patch the CYCLE output of the Smooth Function into the IN jack. Monitor the OUTPUT while turning the RATE knob full clockwise. The pitch should be about 100 Hz, and should go to sub-audio rates (as seen from the LED'S) when the knob is turned down. Check that a control voltage into the VC IN jack will control the rate. Note that this is an attenuating input only, with no inverting processing.'' ▲''A high level applied to the HOLD input (greater than about 4.5 volts) should stop the Smooth Function from cycling. With the Smooth Function patched to cycle, connect the CYCLE of the Smooth Function into the SAMPLE input of the Stepped Function. Patch the Stepped Function CYCLE to its IN jack. Using the STEPPED OUT to control the pitch of an oscillator, listen for the pitch change motion as the Stepped RATE is turned up. When fully clockwise, a triangular "staircase" waveform will be generated by the Stepped Function Generator. For best audible rate, the Smooth Function should be fairly slow. As the Stepped RATE knob is turned down, the staircase will slow down.'' Note: I was unable to get a satisfactory result from the Stepped function using these procedures, instead simply adjusting the trimmer until it worked as expected. Line 187 ⟶ 183: === Notes === * 330R refers to 330 ~~ohms~~Ohms. ~~100n~~100nF = 0.1 uF. * PCB is 6" x 2" with 3mm mounting holes 0.15" in from the edges. == CC-BY-NC == Readers are permitted to construct these circuits for their own personal use only. Ken Stone retains all rights to his work. Serge Tcherepnin retains all rights to his work. == See also == * [[CGS Serge smooth and stepped generator]] for the latest version. * [[CatGirl_Synth#The_CGS_modules\|The CGS modules]] * [[CGS parts FAQ]] == References == * ''[https://web.archive.org/web/~~20180209234737fw_~~20180209234737f/http://www.CGS.synth.net:80/modules/CGSssg_ssg.html Smooth and Stepped Generator for music synthesizers.]'' ~~(archived)~~ by Ken Stone, 2011, with permission of the author - archived {{reflist}} == External links == * [http://groups.yahoo.com/group/CGS_synth CGS Synth discussion group], for discussion of locating parts, modifications and corrections etc. [[Category:CGS ~~modular~~CV processors]] [[Category:CGS CV generators/controllers]]