Impedance Control PCB: Structures, Tolerances and Testing What Impedance Control Means in Practice Impedance control is the discipline of making a trace behave as a transmission line of a defined characteristic impedance rather than as a wire. On a controlled impedance board, a signal trace of a given type presents…

Defence System PCB Manufacturing: Prototype to Volume Reliability as a Precondition In commercial electronics, reliability is a competitive advantage. In defence electronics it is the entry requirement. Radar, encrypted communications, guidance and fire control, and intelligence and surveillance platforms all depend on electronics that work the first time and continue…

Aircraft Landing Gear PCB: Aerospace Control Electronics Where the Electronics Sit Landing gear carries the aircraft on the ground, retracts and extends in flight, and stops the aircraft on the runway. Each of those functions has an electronic control unit behind it, and each of those control units is built…

Mixing Console PCB: Grounding, Assembly and Testing What Makes an Audio Board Different A mixing console is judged by what the operator hears, and at low levels what they hear is the residual noise and distortion of the electronics. Audio signals arrive at microphone level, in the millivolt range, and…

Spectrum Analyzer PCB: Design for a Low Noise Floor The Board Sets the Noise Floor A spectrum analyser measures the amplitude distribution of a signal across frequency, and what it can see is limited by its own noise floor. That floor is set by the receiver chain, and the receiver…

Back Drilling PCB: Removing Via Stubs for High Speed The Problem a Via Stub Creates A through hole via runs the full thickness of the board. When the signal only needs to travel between two inner layers, the portion of the barrel below the connection point serves no electrical purpose.…

Graphic PCB: Printing Interfaces Directly on the Board What a Graphic PCB Is A graphic PCB does two jobs on one substrate. It carries the circuit, and it carries the interface: the icons, function labels, scale markings, logos and area divisions that a person reads and touches. The graphics are…

Signal Generator PCB: Design for Phase Noise and Stability The Board Sets the Noise Floor A signal generator is an instrument, and its specification is a set of numbers: frequency accuracy, long term stability, phase noise, harmonic and spurious content, and output flatness. Those numbers are determined partly by the…

ABS Control Module PCB Assembly: Safety Critical Build The Electronics Behind an Active Safety System An anti lock braking system watches wheel speed, calculates slip in real time, and modulates hydraulic pressure at each wheel to prevent lock up. The control module is the unit that does the calculating, and…

Microwave Transmitter PCB: Materials, Stackup and Thermal A Board Operating at the Limit of Its Materials A microwave transmitter runs continuously at high frequency and often at high power. That combination puts the board under simultaneous electrical and thermal stress, and it removes most of the margin that ordinary RF…