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diff --git a/electrical-specifications.typ b/electrical-specifications.typ new file mode 100644 index 0000000..6d73b5e --- /dev/null +++ b/electrical-specifications.typ @@ -0,0 +1,587 @@ +#import "@preview/unify:0.8.1": qty, qtyrange + += Electrical specifications <electrical-specifications> + +== Signal standards <signal-standards> + +=== Voltage range <voltage-range> + +There are three types of signals used in the SAME format: + ++ Bipolar signals, ranging from $qty(-10, "V")$ to $plus qty(10, "V")$. ++ Unipolar signals, ranging from $qty(0, "V")$ to $plus qty(10, "V")$. ++ Gate signals, which are either $qty(0, "V")$ (low) or $plus qty(10, "V")$ + (high). Gates represent momentary states, such as a computation error (e.g. + input out of bound) or a logic result (a truthful value being represented as a + high gate). By convention, and to ensure compatibility with other formats, + gate inputs must have a threshold of $plus qty(2.5, "V")$, determined either + at the rising edge or at voltage level (the behavior must be specified in + individual module documentation). + +==== Banana format <banana-format> + +All IO, except when interfacing with other formats, is done on $qty(4, "mm")$ +banana jacks. Banana jacks are stackable and allow passive signal distribution +without the need of dedicated modules. They also allow, when short protection is +strictly enforced (which is the case of SAME format) passive averaging of +outputs: When two short-protected outputs are stacked, the equal output +impedances form a voltage divider, producing the arithmetic mean. + +They are standard on a lot of lab equipment such as digital multimeters. +Their standard spacing ($qty(0.75, "inch")$ grid) allows the use of standard +shorting bars. Furthermore, they are sturdy and reliable. + +However, being unshielded and ungrounded, banana jacks act as RF antennas. This +effectively limits the SNR of the SAME format to $qty(95, "dB")$. This +$qty(95, "dB")$ limit is above the Metrologic tier target of $qty(90, "dB")$, so +banana jacks do not constrain the achievable SNR. + +Users should prefer high quality cables (Pomona or equivalent), +silicone-wrapped, and use the shortest cable length necessary. + +Note that the noise floor of the system can be improved beyond the standard +limitations of banana jacks by using shielded cables with single-ended +grounding. However, to maintain compatibility and accessibility, modules must +not require such cables for normal operation. + +==== Inputs requirements <inputs-requirements> + +All inputs utilize white jacks. They must accept bipolar voltages across the +full $plus.minus qty(10, "V")$ range and the full DC to #qty(20, "kHz") +bandwidth, with precision conforming to the module's declared tier. All inputs +must have an impedance $gt.eq qty(1, "mega ohm")$ (Hi-Z). Inputs must be +protected against RF-induced noise received via the patch cable. RF signals +above 1MHz must be attenuated by at least 40dB at the input. + +===== Out-of-domain handling strategies <out-of-domain-handling-strategies> + +While all inputs must accept bipolar signals, some mathematical functions do not +accept the full range (e.g. logarithm, division, etc.). In that case, the module +must include an out-of-domain handling strategy, and document it: + +#figure( + table( + columns: (auto, auto, auto), + table.header([*Strategy*], [*Description*], [*Example use cases*]), + [Clamp], [Output held at boundary], [Logarithm], + [Hold], [Freeze last valid output], [Integrator], + [Fold], [Reflect at boundary], [Chaotic attractor], + [Wrap], [Wrap around range], [Phase accumulator], + [Oscillate], [Bounded, specified oscillation], [Implicit function solver], + [Zero], [Output $qty(0, "V")$], [Divider], + [Passthrough], [Input passes unchanged], [Signal conditioner], + ), + caption: [Out-of-domain handling stategies], +) <table-out-of-domain-handling-strategies> + +When such a case occurs, an error gate must be fired on a dedicated error jack +output. On multiple channels modules, there should be one such error gate per +channel. + +==== Output requirements <output-requirements> + +Outputs can be either bipolar signals (light blue jack), unipolar signals (light +yellow jack) or gate signals (red jack). + +All outputs must have an impedance $lt.eq qty(10, "ohm")$. This ensures that any +output can be patched into any number of inputs without signal degradation or +loss. Outputs must be short-circuit protected, with fault current limited to +$lt.eq qty(10, "mA")$. + +===== Loading error <loading-error> + +With $Z_"out" lt.eq qty(10, "ohm")$ and $Z_"in" gt.eq qty(1, "mega ohm")$, the +worst-case single-connection loading error is 10ppm, compatible with Metrologic +tier precision. When stacking multiple inputs on a single output via banana +jacks, the parallel input impedance must be considered: + +#figure( + table( + columns: (auto, auto, auto), + table.header([*Inputs stacked*], [*Parallel $Z_"in"$*], [*Loading error*]), + [1], [$qty(1, "mega ohm")$], [$qty(10, "ppm")$], + [4], [$qty(250, "kilo ohm")$], [$qty(40, "ppm")$], + [10], [$qty(100, "kilo ohm")$], [$qty(100, "ppm")$], + [40], [$qty(25, "kilo ohm")$], [$qty(400, "ppm")$], + ), + caption: [Loading error per inputs stacked], +) <table-loading-error> + +Module designers should document expected fan-out in module specifications. For +typical patches ($lt.eq 10$ connections per output), loading error remains a +small fraction of the Industrial tier budget. + +===== Error gates <error-gates> + +Modules whose mathematical function can produce out-of-domain or internal error +conditions must provide error gates. Modules that cannot produce such conditions +(e.g., a simple attenuator) are exempt. + +Error gates are also considered valid signals and should use $qty(4, "mm")$ red +banana jacks. Modules designers should strive to have one error gate output per +error type per channel. Space constraints may force the module designer to +aggregate multiple error gates (OR operator). In that case, out-of-domain and +internal errors must never be aggregated. + +#figure( + table( + columns: (auto, auto), + table.header([*Source*], [*Category*]), + [Clipping], [Internal], + [PWAM Soft Saturation], [Internal], + [Domain Violation], [Out-of-Domain], + [Passthrough Active], [Out-of-Domain], + [Servo Unlock], [Internal], + ), + caption: [Examples of error gates], +) <table-examples-of-error-gates> + +=== Bandwidth <bandwidth> + +All signal inputs on a SAME system must accept and give mathematically correct +results for a rate of change ranging from DC ($qty(0, "Hz")$) to at least +$qty(20, "kHz")$). Precision specifications apply within this bandwidth. Are +excluded from this requirement only signals coming from the outside, through +interface modules. In that case, the signal must respect the specifications of +the incoming signal format. + +==== Signals interpretation <signals-interpretation> + +All signals are voltages. Any signal can be used in place of any other signal. +Interpretation of the function of a signal is left to individual module +implementation and computation context (a control voltage in one computation can +be a logic result in another, or a function variable, etc.). + +== Precision tiers <precision-tiers> + +=== General specification <general-specification> + +We define three precision tiers, with varying precision requirements. Those +three precision tiers must target the same signal range of DC to +$qty(20, "kHz")$ as specified in the signal standards. + +A change of precision tier must not induce a change of PCB: if needed, the PCB +designs should include multiple footprints (notably for various size capacitors) +or jumpers (if a specific sub circuit can be disabled for a lower precision +tier). + +All SAME-compliant designs must at least provide a BOM for the metrologic +precision tier. + +==== Precision measurements conditions <precision-measurements-conditions> + +All precision metrics are measured after one hour of warm-up from a cold start +at ambient temperature. This allows the oven-compensated components to warm-up, +temperature gradients to stabilize, and servo loops to settle. + +===== Temperature <temperature> + +Measurements are made with an ambient temperature range of +$qtyrange(15, 30, "dC", delimiter: "\"to\"")$, with an hourly variation of +maximum $plus.minus qty(2, "dC")$. Temperature is the main source of drift for +components. While designs should compensate for reasonable temperature +variations, they should expect normal temperature operation conditions, +achievable with a standard HVAC. + +===== Humidity <humidity> + +Measurements are made within a relative humidity range of +$qtyrange(30, 70, "percent", delimiter: "\"to\"") "RH"$, with an hourly variation of +maximum $plus.minus qty(5, "percent") "RH"$. + +High humidity can cause parasitic leakage paths (nanoamps matter at high-Z +nodes), dielectric changes affecting precision capacitors, and long-term +corrosion. Low humidity can cause electro-static discharges (ESD) risk during +handling and static charge accumulation. + +These requirements ensure that those risks are mostly avoided. They should be +met with easy access humidity control measures and tools. + +===== Atmospheric pressure <atmospheric-pressure> + +Measurements are made within an atmospheric pressure range from +$qtyrange(800, 1100, "hPa", delimiter: "\"to\"")$, with a daily variation of +maximum $plus.minus qty(50, "hPa")$. + +A low atmospheric pressure impacts convection and temperature regulation. It +also reduces the dielectric strength of the air, inducing a higher risk of +arcing and breakdown. + +Some types of capacitors, relays and switches are sensitive to atmospheric +pressure. The recommended pressure range should allow operation from sea level +to $qty(2000, "m")$ altitude, under normal atmospheric conditions. + +===== Electro-magnetic environment <electro-magnetic-environment> + +RF field immunity must follow EN 61000-4-3 specification ( +$qty(3, "volt per meter")$, $qtyrange(80, 1000, "MHz")$). The magnetic field +should be below $qty(1, "ampere per meter") "DC"$, and below +$qty(0.3, "ampere per meter") "AC"$ (power frequency). SAME equipment should be +at least $qty(1, "m")$ away from switching equipment such as motors, welders +etc. + +While SAME provides strong internal shielding, external electro-magnetic +interference (EMI) beyond specification may degrade the SNR. + +===== Air quality <air-quality> + +SAME equipment should be operated indoors, with clean dust filters (recommended +monthly cleaning). Corrosive gases such as $H_2 S$, $"Cl"_2$, $S O_2$, etc, +conductive particles and salt spray (coastal environment) are not permitted. + +Dust reduces cooling efficiency and can introduce leakage paths. Corrosive gases +degrade the components and contacts. Conductive particles can create short +circuits and leakages. Salt spray is corrosive. + +Those requirements should be met with indoor operation in air-filtered rooms. + +===== Mechanical environment <mechanical-environment> + +SAME equipment should be operated on stable surfaces, free from significant +vibration. Vibration can induce microphonic effects in capacitors and +connectors, affecting precision at high-impedance nodes. + +Operating vibration should be below $qty(0.5, "g")$ ($qtyrange(5, 500, "Hz")$). +Shock should be below $qty(5, "g")$ ($qty(11, "ms")$ pulse). + +These requirements should be met in normal laboratory or studio environments. + +===== Lighting <lighting> + +Direct sunlight on the chassis should be avoided during precision operation. +Sunlight causes localized heating and thermal gradients. Some precision +semiconductors are photosensitive. + +Normal indoor lighting is acceptable. Modules should not be operated with +cassettes removed in bright light. + +===== Ionizing radiation <ionizing-radiation> + +SAME is designed for normal background radiation environments (below +$qty(1, "micro sievert per hour")$). + +Operation near significant ionizing radiation sources such as medical imaging +equipment, nuclear facilities, or particle accelerators is not recommended +without appropriate shielding. Ionizing radiation can increase semiconductor +leakage currents and cause single-event effects. + +At altitudes approaching $qty(2000, "m")$, cosmic ray flux increases +approximately $3 times$ compared to sea level. This is however unlikely to +significantly impact analog precision. + +SAME is not radiation-hardened. Applications requiring radiation tolerance +should seek specialized equipment. + +====== Radioactive source modules <radioactive-source-modules> + +Some SAME modules (such as true random voltage generators based on radioactive +decay) may contain low-activity sealed radioactive sources. + +These modules: +- Must comply with local regulations regarding exempt-quantity radioactive + materials. The SAME specification does not mandate specific isotopes or + activities; +- Must provide adequate shielding to not affect adjacent modules; +- Must be clearly labeled with radiation symbol and source information; +- Must include handling and disposal instructions. + +The presence of a radioactive source module does not affect the precision +specifications of other modules in the system, provided shielding requirements +are met. + +===== Summary <precision-measurements-conditions-summary> + +#figure( + table( + columns: (auto, auto, auto), + table.header([*Parameter*], [*Range*], [*Variation*]), + [Temperature], [$plus qty(15, "dC") "to" plus qty(30, "dC")$], [$plus.minus qty(2, "celsius per hour")$], + + [Relative humidity], + [$qtyrange(30, 79, "percent", delimiter: "\"to\"") "RH"$], + [$plus.minus qty(5, "percent") "RH"$], + + [Atmospheric pressure], [$qtyrange(800, 1100, "hPa")$], [$plus.minus qty(50, "hecto pascal per day")$], + + [RF immunity], [$qty(3, "volt per meter"), qtyrange(80, 1000, "MHz")$], [N/A], + + [Magnetic field (DC)], [$lt qty(1, "ampere per meter")$], [N/A], + [Magnetic field (AC)], [$lt qty(0.3, "ampere per meter")$], [N/A], + [Vibration], [$lt qty(0.5, "g"), qtyrange(5, 500, "Hz")$], [N/A], + [Shock], [$lt qty(5, "g"), qty(11, "ms")$], [N/A], + [Air quality], [Indoor, filtered], [N/A], + [Lighting], [No direct sunlight], [N/A], + [Background radiation], [$lt qty(1, "micro sievert per hour")$], [N/A], + ), + caption: [Summary of the precision measurements conditions], +) <table-precision-measurements-conditions-summary> + +Note that electrical supply requirements will be discussed in +#ref(<power-distribution>). + +=== Educational tier <educational-tier> + +This tier aims for a precision of $qty(0.1, "percent")$ ($qty(1000, "ppm")$), and a SNR of +$qty(70, "dB")$. This tier is intended for lowering the barrier of entry by +reducing the components costs and soldering difficulty. It is suitable for +teaching on circuit topologies and general analog computer patching. At this +level of precision, results are valid within $plus.minus qty(10, "mV")$. + +The maximum drift rate should be inferior or equal to $qty(60, "ppm per hour")$. +We recommend calibration verification before each session. + +=== Industrial tier <industrial-tier> + +This tier aims for a precision of $qty(0.01, "percent")$ ($qty(100, "ppm")$), and a SNR of +$qty(80, "dB")$. This tier is intended for research, serious experimentation, +and applications requiring repeatable results. It is suitable for control +systems modeling, audio-rate computation, and scientific data acquisition. At +this level of precision, results are valid within $plus.minus qty(1, "mV")$. + +The maximum drift rate should be inferior or equal to +$qty(0.6, "ppm per hour")$. We recommend daily calibration verification. + +=== Metrologic tier <metrologic-tier> + +This tier aims for a precision of $qty(0.001, "percent")$ ($qty(10, "ppm")$), and a SNR of +$qty(90, "dB")$. This tier is intended for precision measurement, long-duration +computation, and applications requiring traceable accuracy. It is suitable for +metrology, reference instrumentation, and extended continuous operation. At this +level of precision, results are valid within $plus.minus qty(0.1, "mV")$. + +The maximum drift rate should be inferior or equal to +$qty(0.014, "ppm per hour")$. We recommend daily calibration verification. + +=== Summary <precision-tiers-summary> + +#figure( + table( + columns: (auto, auto, auto, auto), + table.header([*Parameter*], [*Educational*], [*Industrial*], [*Metrologic*]), + [*Precision*], + [$qty(0.1, "percent") (qty(1000, "ppm"))$], + [$qty(0.01, "percent") (qty(100, "ppm"))$], + [$qty(0.00, "percent")% (qty(10, "ppm"))$], + + [*SNR*], [$qty(70, "dB")$], [$qty(80, "dB")$], [$qty(90, "dB")$], + [*Result validity*], [$plus.minus qty(0.1, "V")$], [$plus.minus qty(10, "mV")$], [$plus.minus qty(1, "mV")$], + + [*Maximum drift rate*], [$qty(60, "ppm per hour")$], [$qty(0.6, "ppm per hour")$], [$qty(0.014, "ppm per hour")$], + + [*Drift-free computation*], [$approx qty(16, "h")$], [$approx qty(7, "day")$], [$approx qty(30, "day")$], + + [*Calibration verification*], [Before each session], [Daily], [Daily], + ), + caption: [Precision tiers summary], +) <table-precision-tiers-summary> + +==== Drift rate derivation <drift-rate-derivation> + +The drift rates are calculated such that total accumulated drift over the +drift-free computation period consumes approximately $qty(100, "percent")$ of the precision +budget. + +#figure( + table( + columns: (auto, auto, auto, auto), + table.header([*Tier*], [*Precision*], [*Drift rate*], [*Time to drift $qty(100, "percent")$ of budget*]), + [*Educational*], [$qty(1000, "ppm")$], [$qty(60, "ppm per hour")$], [$approx qty(16, "h")$], + + [*Industrial*], [$qty(100, "ppm")$], [$qty(0.6, "ppm per hour")$], [$approx qty(7, "day")$], + + [*Metrologic*], [$qty(10, "ppm")$], [$qty(0.014, "ppm per hour")$], [$approx qty(30, "day")$], + ), + caption: [Drift rate derivations], +) <table-drift-rate-derivation> + +== Power distribution <power-distribution> + +=== Precision tiers <power-distribution-precision-tiers> + +We believe that a single system should be able to aggregate modules from +different precision tiers. Power distribution is not a soldering build +accessible to the average builder, due to the integration with mains voltage +(shock risk). For this reason, SAME only admits one set of constraints for the +power distribution, targeting metrologic tier. + +=== Provided power <provided-power> + +==== Power rails <power-rails> + +Power distribution must provide the following voltages: +- $plus.minus qty(15.00, "V")$: Used to power op-amps. +- $plus.minus qty(10.0000, "V")$ Force + Sense (Kelvin Connection): Reference + Voltages used to ensure $qty(10, "ppm")$ precision. +- $qty(10, "MHz")$ Master Oscillator: A high-stability, low-phase-noise sine + wave reference for time-domain computations. +- Stagger ($0$ or $plus qty(15, "V")$, indicates port parity): Used for + time-domain computation cores frequency stagger relative to the master + oscillator’s frequency. +- Analog Ground (AGND): Analog signals return path. +- Digital Ground (DGND): Digital signals return path. +- $plus.minus qty(5.0, "V")$ Digital ($"VD"$): Used to power CMOS and Timers. +- Chassis Earth: For high voltage protection and EMF shielding. + +Note that in this list we use the significant figure convention systematically +to indicate precision requirements. + +==== Power budget <power-budget> + +For 8 modules, the total power budget per $plus.minus qty(15.00, "V")$ rail is +$qty(1.5, "A")$. This permits the use of easily available power supplies for +rack chassis, while giving enough power for compute modules. The total power +budget per $plus.minus qty(5, "VD")$ rail is $qty(800, "mA")$. + +For each module, this means: $approx qty(185, "mA")$ on the +$plus.minus qty(15.00, "V")$, and $qty(100, "mA")$ on the +$plus.minus qty(5, "VD")$ rails. + +==== PWAM frequency staggering <pwam-frequency-staggering> + +To limit drift and increase precision in multipliers and time-domain functions, +the system utilizes a global timebase. + +/ Master Oscillator: All modules performing time-domain operations (PWAM, + integration timing, etc.) must accept a $qty(10, "MHz"), qty(1, "Vpp")$ (into + $qty(50, "ohm")$) sine wave via the rear BNC connector. Modules operating + purely in the continuous voltage domain (e.g., standard summers, log amps) may + ignore it. +/ Staggering: Neighboring modules using PWAM should not operate at identical + switching phases/frequencies to prevent intermodulation. The Stagger rail on + the DB-25 connector determines the derivation of the local carrier from the + Master Oscillator. + - Modules receiving $qty(0, "V")$ from the Stagger rail must lock their + carrier frequency to exactly $qty(500, "kHz")$ ($"Master"/20$) with + $qty(0, "degree")$ phase shift. + - Modules receiving $plus qty(15, "V")$ from the Stagger rail must lock their + carrier frequency to $qty(500, "kHz")$ ($"Master"/20$) with a + $qty(90, "degree")$ phase shift, that should be derived via quadrature + division referenced to the $qty(10, "MHz")$ Master. + +==== Cleanliness requirements <cleanliness-requirements> + +===== $plus.minus qty(15.00, "V")$ analog supply requirements +<analog-supply-requirements> + +At the module connector, the $plus.minus qty(15.00, "V")$ rails shall maintain +an initial accuracy within $plus.minus qty(7.5, "mV")$ ($plus.minus qty(0.05, "percent")$) at +$qty(25, "dC")$. Line regulation shall be better than $plus.minus qty(1.5, "mV")$ +($qty(0.01, "percent")$) for a $plus.minus qty(10, "percent")$ input voltage variation. Load regulation shall +be better than $plus.minus qty(3.0, "mV")$ ($qty(0.02, "percent")$) over the +full load range ($qtyrange(10, 100, "percent", delimiter: "\"to\"")$). Output +voltage ripple and noise shall not exceed $qty(500, "uVpp")$ over a +$qty(20, "MHz")$ bandwidth. + +===== $plus.minus qty(5.0, "VD")$ digital supply requirements +<digital-supply-requirements> + +The $plus.minus qty(5.0, "VD")$ rails shall maintain an initial accuracy within +$qty(25, "mV")$ ($plus.minus qty(0.5, "percent")$) at $qty(25, "dC")$. Line +regulation shall be better than $plus.minus qty(5, "mV")$ +($qty(0.1, "percent")$) for a $plus.minus qty(10, "percent")$ input voltage +variation. Load regulation shall be better than $plus.minus qty(10, "mV")$ +($qty(0.2, "percent")$) over the full load range. Output voltage ripple and +noise shall not exceed $qty(5, "mVpp")$ over a $qty(20, "MHz")$ bandwidth. + +===== $plus.minus qty(10.0000, "V")$ reference requirements +<reference-requirements> + +The $plus.minus qty(10.0000, "V")$ reference rails shall maintain an initial +accuracy within $plus.minus qty(20, "uV")$ ($plus.minus qty(2, "ppm")$) at +$qty(25, "dC")$. Line regulation shall be strictly less than +$qty(2, "micro volt per volt")$ ($qty(0.2, "ppm per volt")$). Load regulation +shall be strictly less than $qty(5, "micro volt per milli ampere")$ +($qty(0.5, "ppm per milli ampere")$). The temperature coefficient must be less +than $qty(0.5, "ppm per celsius")$, and low-frequency noise +($qtyrange(0.1, 10, "Hz", delimiter: "\"to\"")$) shall not exceed +$qty(2, "uVpp")$. + +===== Master oscillator requirements <master-oscillator-requirements> + +The $qty(10, "MHz")$ Master Oscillator shall demonstrate frequency stability +inferior or equal to $qty(10, "ppb")$ (parts per billion) over the full +operating temperature range. Phase noise shall be inferior or equal to +$qty(-140, "dBc per Hz")$ at a $qty(1, "kHz")$ offset. + +===== Grounding rules <grounding-rules> + +- Analog returns to AGND only. +- Digital returns to DGND only. +- Modules shall not bridge AGND and DGND. Modules containing both analog and + digital circuitry must maintain internal ground separation and connect each + to the appropriate backplane ground. +- Chassis Earth is only used for chassis grounding, EMF shielding and high + voltage protection. +- The power distribution board should provide state of the art ground management + (e.g. star point). + +=== Power distribution calibration <power-distribution-calibration> + +At power distribution board level, we do not have access to a source of truth +for automatic calibration. We must accept manual, repeatable calibration +methods. This method should be insensitive to drift (in opposition to trimmers +that are notoriously unstable). + +To ensure high precision without drift as specified in the precision tiers +section, the $plus.minus qty(10.0000, "V")$ must be calibrated. The only +accepted method of calibration is Drift-Free, discrete steps, repeatable +topologies, for instance: through two switches (coarse, fine) into a resistor +ladder (R2R) digital-to-analog converter (DAC). The switches must be accessible +on the chassis front panel, next to a $plus qty(10.0000, "V")$ reference, a +$qty(-10.0000, "V")$ reference and an AGND jack (respectively yellow, blue and +black). + +The other power rails may also be calibrated, through dip-switches and R2R DACs +on the power distribution board PCB. + +==== Standby switch <standby-switch> + +Since the reference voltages depend on an oven stabilized buried zener diode and +an ovenized crystal oscillator, the front panel must provide a standby switch, +to shut down the unit while maintaining the diode at temperature. The standby +mode power consumption should not exceed 200mA. + +#figure( + [``` + Calibration Coarse: Position X + Calibration Fine: Position Y + +15.00V DIP: 0bXXXXXXXX + -15.00V DIP: 0bXXXXXXXX + Ambient Temperature: XX°C + Date: YYYY-MM-DD + Reference DMM: [model, cal date] + ```], + caption: "Example of calibration log", +) <example-calibration-log> + +=== Backplane connector <backplane-connector> + +Power is distributed from the power distribution board to modules with a +DB-25 cable: female port panel mounted on module cassette, and PCB mounted on +power distribution board, a short DB-25 male to male cable is used to connect +the cassette to the power distribution board. D-sub connectors are ubiquitous, +sturdy and shielded. + +#figure( + table( + columns: (auto, auto, auto, auto), + table.header([*Pin*], [*Signal*], [*Pin*], [*Signal*]), + [1], [$plus qty(15.00, "V")$], [14], [AGND], + [2], [$plus qty(15.00, "V")$], [15], [AGND], + [3], [$qty(-15.00, "V")$], [16], [AGND], + [4], [$qty(-15.00, "V")$], [17], [DGND], + [5], [AGND], [18], [DGND], + [6], [AGND], [19], [$plus qty(5.0, "VD")$], + [7], [AGND], [20], [$qty(-5.0, "VD")$], + [8], [$plus qty(10.0000, "V")$ Force], [21], [Stagger], + [9], [$plus qty(10.0000, "V")$ Sense], [22], [_Reserved_], + [10], [$qty(-10.0000, "V")$ Force], [23], [_Reserved_], + [11], [$qty(-10.0000, "V")$ Sense], [24], [_Reserved_], + [12], [AGND], [25], [Chassis Earth], + [13], [AGND], [Shell], [Chassis Earth], + ), + caption: "DB-25 backplane connector pin allocation", +) <table-backplane-connector> + +The $qty(10, "MHz")$ Master Oscillator is distributed via a dedicated rear-panel +BNC connector, not through the DB-25 backplane connector. |