{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.digital-comparator","code":"thing-q1780800","url":"https://ver.cy/models/thing/q1780800/","name":"digital comparator","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.OBJ"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A digital comparator is a logic circuit that compares two digitally encoded values and indicates equality or, for a magnitude comparator, their relative numerical order.","purpose":"Enable an agent to recognise a digital comparator, assess whether its comparison results are valid, and determine how it may be connected, configured and used.","scope":{"in":["Equality and magnitude comparison of digital input words","Operand width, encoding, significance and comparison semantics","Comparison outputs, enables and cascade connections","Electrical compatibility, propagation timing and output validity","Verification and fault assessment specific to comparison behaviour"],"out":["Analogue voltage comparators and their threshold or hysteresis behaviour","Dimensional measuring instruments marketed as digital comparators","General-purpose processors and complete arithmetic logic units","Software-only comparison operators and sorting algorithms","Individual product inventories, ownership and procurement records"],"boundaries":[]},"distinguishingFeatures":["Accepts discrete digital operands and derives a relation between them rather than comparing continuously varying analogue voltages.","Provides equality or ordering information as its functional result rather than requiring a user to interpret an arithmetic difference.","A magnitude comparator distinguishes operand ordering; an equality-only comparator need not report which operand is greater.","The intended referent compares encoded words rather than measuring physical displacement and displaying a digital reading."],"structure":{"bundles":[{"id":"comparison-semantics","name":"Comparison semantics","description":"The relations computed and the meaning assigned to input words.","layers":[{"id":"operand-meaning","name":"Operand meaning","description":"Word boundaries, bit significance and numerical interpretation.","findings":[{"id":"operand-interpretation","name":"Operand interpretation","description":"Record the interpretation required to turn input bit patterns into comparable values.","questions":[{"text":"How many bits form each operand, and which inputs carry the most and least significant bits?","id":"operand-interpretation-q01","kind":"definition"},{"text":"Are operands interpreted as unsigned binary, a specified signed encoding or another encoding?","id":"operand-interpretation-q02","kind":"definition"}]}]},{"id":"relation-meaning","name":"Relation meaning","description":"Supported comparisons and their observable representation.","findings":[{"id":"relation-output-contract","name":"Relation output contract","description":"Record which relations are available and how their assertion is represented.","questions":[{"text":"Does the implementation report equality only, or also A greater than B and A less than B?","id":"relation-output-contract-q01","kind":"definition"},{"text":"What output polarity or encoding identifies each relation, and which combinations are valid after settling?","id":"relation-output-contract-q02","kind":"definition"}]}]}]},{"id":"logic-interface","name":"Logic interface","description":"Electrical conditions under which operands and results represent valid digital signals.","layers":[{"id":"input-and-supply-conditions","name":"Input and supply conditions","description":"Supply requirements and recognition of operand and control levels.","findings":[{"id":"valid-input-levels","name":"Valid input levels","description":"Record documented electrical limits for interpreting input signals.","questions":[{"text":"Which supply range and input-high and input-low limits apply under the intended operating conditions?","id":"valid-input-levels-q01","kind":"measurement"},{"text":"How must unused operand, enable and cascade inputs be terminated?","id":"valid-input-levels-q02","kind":"action"}]}]},{"id":"output-loading","name":"Output loading","description":"How relation outputs connect to receiving logic.","findings":[{"id":"relation-signal-drive","name":"Relation signal drive","description":"Record output topology and loading constraints for each comparison signal.","questions":[{"text":"What output topology, external pull components and drive limits are documented?","id":"relation-signal-drive-q01","kind":"definition"},{"text":"Do the receiving thresholds and actual load permit each relation output to reach a valid level?","id":"relation-signal-drive-q02","kind":"measurement"}]}]}]},{"id":"timing-and-validity","name":"Timing and validity","description":"When comparison outputs may be trusted after operand or control changes.","layers":[{"id":"comparison-latency","name":"Comparison latency","description":"Combinational or clocked behaviour and the associated timing contract.","findings":[{"id":"result-availability","name":"Result availability","description":"Record the delay or sampling conditions separating an input change from a usable result.","questions":[{"text":"Is the comparison path combinational, registered or otherwise sequenced?","id":"result-availability-q01","kind":"definition"},{"text":"What propagation or clock-related timing limits apply at the actual supply, temperature and output load?","id":"result-availability-q02","kind":"measurement"}]}]},{"id":"transient-and-disabled-behaviour","name":"Transient and disabled behaviour","description":"Interpretation of outputs outside normal stable comparison.","findings":[{"id":"invalid-result-handling","name":"Invalid result handling","description":"Record conditions in which outputs must not be treated as a valid operand relation.","questions":[{"text":"What output behaviour is documented during power-up, disable, reset or changing operands?","id":"invalid-result-handling-q01","kind":"definition"},{"text":"What settling interval, register or qualification signal prevents downstream action on transient results?","id":"invalid-result-handling-q02","kind":"action"}]}]}]},{"id":"word-extension-and-integration","name":"Word extension and integration","description":"Composition of comparator stages and adaptation to a larger digital system.","layers":[{"id":"cascade-composition","name":"Cascade composition","description":"Supported inter-stage relation signals and significance ordering.","findings":[{"id":"cascade-contract","name":"Cascade contract","description":"Record whether and how comparator stages form a wider comparison.","questions":[{"text":"Does the implementation support cascading, and what meaning does it assign to each cascade input?","id":"cascade-contract-q01","kind":"definition"},{"text":"How must stages be ordered and standalone cascade inputs initialised to preserve word significance?","id":"cascade-contract-q02","kind":"action"}]}]},{"id":"operand-adaptation","name":"Operand adaptation","description":"Preparation of system values for the comparator's supported representation.","findings":[{"id":"representation-boundary","name":"Representation boundary","description":"Separate the comparator's native behaviour from transformations performed by surrounding logic.","questions":[{"text":"Which truncation, extension, bit reordering or encoding conversion occurs before comparison?","id":"representation-boundary-q01","kind":"boundary"},{"text":"What evidence establishes that these transformations preserve the ordering or equality required by the application?","id":"representation-boundary-q02","kind":"provenance"}]}]}]},{"id":"verification-and-fault-isolation","name":"Verification and fault isolation","description":"Evidence that observed outputs implement the intended comparison under stated conditions.","layers":[{"id":"functional-test-coverage","name":"Functional test coverage","description":"Test cases that exercise equality, significance and interpretation boundaries.","findings":[{"id":"discriminating-test-vectors","name":"Discriminating test vectors","description":"Record test inputs and expected relations derived from the declared comparison semantics.","questions":[{"text":"Which vectors test equal words, single-bit differences and a most-significant difference opposed by lower bits?","id":"discriminating-test-vectors-q01","kind":"action"},{"text":"Which additional vectors cover signed boundaries, enables or cascade stages when those features are present?","id":"discriminating-test-vectors-q02","kind":"action"}]}]},{"id":"fault-evidence","name":"Fault evidence","description":"Observed failures and evidence linking them to a specific comparison path or condition.","findings":[{"id":"comparison-failure-isolation","name":"Comparison failure isolation","description":"Record reproducible mismatches and the checks needed to identify their cause.","questions":[{"text":"For each mismatch, what operands, controls, supply conditions and sampling time were observed?","id":"comparison-failure-isolation-q01","kind":"measurement"},{"text":"Which checks distinguish swapped operands, reversed bit order, incorrect cascade inputs, stuck signals and premature sampling?","id":"comparison-failure-isolation-q02","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of digital comparator this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Identify a digital comparator in a circuit or design and state what it compares, equality or magnitude.","Check its behaviour with test vectors on systems the agent is authorized to change."],"mustNot":["Present an equality comparator as if it reports greater or less.","Change comparator logic in a safety-related controller without review and testing.","Ignore signed versus unsigned encoding when stating a comparison result.","Hide timing faults that can give wrong outputs at speed."],"requiresHuman":["Deploying changed comparison logic in safety-critical or financial systems.","Approving a design after a failed verification test."]},"ethics":{"considerations":["Comparators decide thresholds in machines, so errors can cause unsafe actions.","Silent logic errors are hard to trace and can harm users who trusted the system."],"affectedParties":["Users of controlled machines","System owners","Engineers"]},"owners":{"steward":"The designer or owner of the system the circuit belongs to.","roles":[],"masterSystems":[]},"relations":[{"target":"Q2858615","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.digital-comparator","Wikidata: Q1780800 (https://www.wikidata.org/wiki/Q1780800)"]},"properties":{"applicability":"required","items":["Comparison capability: equality-only; magnitude; configurable","Operand width: bits per operand","Operand interpretation: unsigned binary; signed encoding specified by implementation; other documented encoding","Input significance mapping: input terminal or signal mapped to operand and bit position","Output convention: documented relation signals, polarity and encoding","Supply and logic interface limits: V for supply and input thresholds; mA for output drive, with operating conditions","Comparison timing: ns for applicable propagation, setup, hold and clock-to-output times","Result validity: valid; settling; disabled; uninitialised; indeterminate; fault suspected","Cascade role: standalone; more-significant stage; intermediate stage; less-significant stage; unsupported"]},"recognition":{"applicability":"required","items":["As hardware, an integrated circuit with a printed part number or a block on a circuit board.","In a design, a block or module labelled as a comparator with two inputs and equality or order outputs."]},"capabilities":{"applicability":"required","items":["Determine whether a documented implementation supports the required operand width and interpretation.","Map operand bits and relation outputs to connected signals.","Configure enables and cascade inputs according to the implementation documentation.","Evaluate whether electrical and timing conditions permit reliable sampling.","Exercise comparison test vectors and isolate wiring, interpretation or timing faults."]},"hazards":{"applicability":"required","items":["Wrong results from signed and unsigned confusion.","Glitches when inputs change near the clock edge.","Unsafe actions triggered by wrong threshold comparisons."]},"interfaces":{"applicability":"required","items":["IEC 60617, issued by the International Electrotechnical Commission, provides graphical symbols for diagrams, including binary logic elements used to represent digital comparison circuits."]},"context":{"applicability":"required","items":["Digital comparators are used in processors, controllers and digital logic systems to determine whether binary values match or which value is larger.","They support address decoding, threshold detection, sorting and control decisions.","They may appear as discrete integrated circuits or as logic blocks within programmable devices and larger circuits."]}},"sources":[{"title":"Wikidata item Q1780800: digital comparator","url":"https://www.wikidata.org/wiki/Q1780800","note":"identity and sense of the item"},{"title":"Wikipedia: Digital comparator","url":"https://en.wikipedia.org/wiki/Digital_comparator","note":"general description of the item"}],"openQuestions":["Does the registry source identify a digital logic comparator, or a dimensional measuring instrument with a digital display?","Does the intended kind include both equality-only and magnitude comparators, and both standalone devices and embedded circuit blocks?","Which authoritative references establish the intended comparison semantics, cascade conventions and representative implementation boundaries?","Which interface standards, operating ranges and qualification requirements apply to documented implementations rather than to the kind universally?","Does an existing Vercy world model already cover this concept, requiring a registry link instead of a separate publication?"],"resources":{"spec":"/models/things/publications/thing-q1780800/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q1780800/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:10:02Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:26+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}