Modular Clocks - Analog, MIDI , PPQN

Modular Clocks ... seems simple at first, but the more you delve into this subject and try to sync
devices from different manufacturers, the more complex things can get.

If you have ever heard the Daft Punk tune "Moroder by Giorgio" you can hear Giorgio talk

about how he synced a Moog Modular.

"I know the synthesizer, why don't I use the synthesizer
Which is the sound of the future"
And I didn't have any idea what to do but I knew I needed a click
So we put a click on the 24-track which was then synced to the Moog modular
I knew that it could be a sound of the future
But I didn't realize how much the impact would be..."

Basic Tempo is made up of beats.
Beats are grouped into bigger units called measures.
Most often, a measure has 2 to 4 beats (though it can really have as many divisions as is desired).
A note which lasts for 1 beat is called a quarter note..... since it divides the average measure into quarters......
For electronic instruments.... this beat is actually a pulse of electricity..... often a 5V to 10V
amplitude pulse which had a regular cycle. This cycle was the sync signal and was used to clock pre midi devices. 

 
With the advent of MIDI, instead of being measured by cycles per second, the time base
was changed to Parts Per Quarter Note (PPQN), also known as pulses per quarter (PPQ), or Pulse (per) quarter note (PQN), and ticks per quarter note (TPQN)

If the time-base divides the instrument into 48 parts, that is called 48 PPQN.

MIDI sequencing hardware and software uses a variable number of timing resolutions. From as little as 24PPQN to 480 PPQN

A sequencer's resolution is defined as its ability to divide the beat of a quarter note into
a pulses. The more pulses, the more accurate a sequencer is.

Common divisions used by sequencers are :
24 parts - 24 ppqn
48 pulses - 48 ppqn
96 parts - 96 ppq
192 ppqn, etc etc etc
 
A module like Pamela's Workout will sync to an external clock input between 1PPQN to 24PPQN.
My Beastek Amoeba trigger module needs a 8 TPQN clock if you require external syncronization.
Note that most analog sequencers send out a pulse every 16th note which equals 4PPQN

MIDI clock = 24 pulses, so called "ticks" per quarter note
Roland equipment (606,707.727,808.909) use 24 pulses per quarter note (PPQN for short), known as DIN Sync24.
A notable Roland exception is the CR-78 which uses 12ppqn.

Korg equipment (eg KPR-77, DDM-110 & DDM-220) uses 48 pulses per quarter note.
(You also need to make a V-trig to S-trig cable).
Oberheim (DMX) & Linn is 96ppqn.
The SCI Drumtraks handles 24, 48, and 96 ppqn
EMU drumulator - 24ppqn - needs a din to 1/4 Y cable

-----------------
Summary:
********************************************************************************
Clock rates                  Equivalent in PPQN              Manufacturer
********************************************************************************
STEP GATE                     1 PPQN ?                         LFO or GATE OUT
 Pre - MIDI                                                              (advances in time on a rising edge and
                                                                                 returns to zero on  a falling edge) 
                                                                                 eg: DOEPFER DARK TIME, Korg SQ-10.
                                                                                 eg: Euro - Zularic Repetitor
                                                                                       (Noise Engineering), Erica Pico Seq &
                                                                                       Pico trigger , Delptronics Triggerman,
                                                                                       Disting Mk3 & 4,
                                                                                       Modcan Touch Sequencer (ext sync)
***************************************************************************
KORG Pulse                2 PPQN                             KORG (SQ-1), Volcas,
                                                                                  Teenage Engineering Pocket Operators
                                                                                  (POs sync on audio pulses,
                                                                                   essentially a click track).
********************************************************************************

STEP CLOCK               4 PPQN                            ARTURIA , DOEPFER MCV 24 – MSY2

or 1/16th                                                                 Korg SQ-1 analog sync , most analog

                                                                              sequencers, Orthogonal Devices ER-101,

                                                                              TipTop Trigger Riot & Circadian Rhythm.

                                                                              Erica Synths Drum Sequencer ,                                                                                                                        1010 Black Box (clock in) 

                                                                              Quite common to find as the default
                                                                              for Eurorack modules.
*********************************************************************************
Euro                              8 or 16 PPQN                    Beastek Amoeba
drum trigger module
********************************************************************************
CR 78  Drum               12PPQN                            Roland
********************************************************************************

MIDI & Sync 24                                                   Modcan Touch Sequencer (Midi sync)

Roland DIN SYNC      24 PPQN                           ROLAND, ARTURIA, ELEKTRON

Computer DAW                                                    Korg SQ-1 MIDI sync, DAW

                                                                            TipTop Trigger Riot & Circadian Rhythm

                                                                              Nerd Seq Mod.clock24 in (XOR)                                                              

***********************************************************************************
KORG DIN                   48 PPQN                         LINN LM-2, ARTURIA, ELEKTRON
Sync 48
********************************************************************************
---------------------------

Step Gate
Starting off with the basic analog clock. ....
This is all pre-MIDI. The signal can be a simple LFO or a gate module producing a square wave. The Doepfer Dark Time  for example can produce a 1 Step gate. A basic analog, pre midi modular will use this form of timing.
This is almost a 1PPQN equivalent.
Most common in Eurorack ... eg Zularic Repetitor, (Noise Engineering),  Erica Synths Pico Seq &
Pico trigger , Delptronics Triggerman,  Disting Mk3 & 4, Modcan Touch Sequencer (ext sync)

Korg Pulse - 2PPQN
Korg SQ-1 sequencers and the Korg Volcas use this standard.
A single KORG pulse is equivalent to just 2 PPQN.

Step Clock (16th clock) - 4PPQN. 
This is an analog trigger. It's equivalent PPQN is 4.( ie four pulses per quarter note
or 1⁄4 the duration of a quarter note.)
It's also called 16th because a note is sent or received every 16th note.
This is quite common to find as a default for Eurorack modules.
This is the most common clock among old analog sequencers.
Devices like the DOEPFER MCV 24 & MSY2 can produce this type of clock.
Also, Eloquencer (Winter Modular)
(So too does the Tip top trigger riot though it can also be set to use 24PPPQ)

MIDI - Sync 24 - Roland DIN Sync - 24PPQN
In the case of MIDI (and Roland DIN Sync), the standard is 24PPQN.
MIDI clock sends a tick 96 times per quarter note.
Lots of old Roland Synths such as the TB303 & TR606, 808, 909 use this standard.
Most DAWs will also use  a 24 PPQN signal
This means that you can have a  triplet for each 8th note. (24/3 = 8)

Korg DIN SYNC - Sync 48 - 48PPQN
Korg has it's own version of DIN Sync.
It uses the same 5 pin cable/socket, but the PPQN is 48.
When syncing Roland and Korg gear via DIN sync, they will work however the Korg machine will run at 1/2 the tempo/speed of the Roland unit.
This can be corrected with several devices which will translate 24-48 sync, such as the Korg KMS-30.
 Korg drums such as the KPR-77, DDM-110 & DDM-220 use 48 sync.
Other devices that use 48 PPQN are the LINN ELECTRONICS LM-2 Drum and some Oberheim Drum Machines.

The Pioneer Toraiz can input & output clock signals of value 1PPQN, 2PPQN, 4PPQN, 24PPQN, 48PPQN.
Synstrom Deluge : Trigger clock output, configurable up to 192 PPQN

Kenton Modsolo - outputs 24PPQN, 48PPQN. 

I understand it can also be set to between 1PPQN to12PPQN (though I haven't tested this).

Links:
Syncing the korg SQ1 with SQ-10


Do let me know if there are any mistakes, errors, or omissions.