Analog Interface Contract
Source, receiver, levels, impedance, common mode, references, cable, transients, and pass/fail evidence.
Analog Audio Interfaces
One Connector Is Not An Interface Specification
An analog connection is defined by the source, receiver, two or more conductors, reference paths, shield, chassis, loading, common-mode range, level, cable, power states, and measurement method. RCA, XLR, TRS, terminal blocks, and proprietary connectors can each carry more than one electrical topology.
Document the complete interface before choosing an adapter, cable, ground change, line driver, receiver, or isolator.
Core References
Single-Ended And Unbalanced
Signal and return current, RCA paths, ground-voltage error, loading, connectors, and conversion.
Balanced And Differential
Impedance balance, differential receivers, floating and active outputs, shield separation, and compatibility.
Common-Mode Rejection
CMRR, source-impedance balance, common-mode range, frequency, level, and installed measurement.
Shield, Chassis, And Signal Reference
Separate cable shield, enclosure, circuit common, signal return, vehicle return, and protective earth.
Galvanic Isolation
Transformers and isolated conversion, loading, saturation, response, hidden conductive paths, and verification.
Cable Loading And Routing
Resistance, capacitance, loop area, shielding, pair balance, connectors, environment, and vehicle routing.
Measurement And Verification
Safe probing, loaded levels, differential and common mode, CMRR, isolation, noise, distortion, and transients.