Amplifiers

Test and measurement amplifiers increase the amplitude of electrical signals with controlled linearity and bandwidth so downstream instruments or systems can measure, analyze, or further process those signals. Typical roles in a lab or system include: preamplification to improve receiver sensitivity, system amplification to restore link losses or drive subsequent stages, buffering or impedance conversion for probes and scopes, distribution of reference frequencies, and specialized synchronous detection (lock‑in amplifiers). Examples in the catalog include low‑frequency, DSP‑based lock‑in instrumentation and ultra‑broadband microwave system amplifiers; each model is optimized for a particular role rather than all roles simultaneously.

Frequency range — defines the band the amplifier can pass or amplify. Catalog examples span from 1 mHz (SR850) to 50 GHz (83050A / 83051A). Gain — small‑signal gain tells how much the amplifier increases low‑level signals; some system amplifiers quote 20–30 dB or higher (for example, the 83050A reports typical gain values around 25 dB in part of its band, while the GT‑1000B is described as delivering up to 40 dB). Noise figure — critical for preamplifiers where sensitivity matters; some microwave system preamps list typical noise figures as low as 6 dB (83050A). Output compression (P1dB) and saturated power — determine usable output level before distortion; the 83020A specifies +30 dBm P1dB in its primary band. Linearity/IP3 — third‑order intercept gives a sense of intermodulation performance (examples: 8449B lists IP3 ≈ +17 dBm typical; 83051A lists +21 dBm typical at one frequency). Impedance, VSWR and connectors — ensure 50 Ω compatibility and connector type (3.5 mm, 2.4 mm, BNC, TekConnect, D‑sub) match the rest of your signal chain. Mechanical, power and interfaces — note DC or AC power requirements, remote interfaces (GPIB, RS‑232) and size/weight constraints when integrating into racks or systems.

Match the amplifier to the primary technical need rather than the largest advertised number. Choose by: frequency band — select a model whose specified band covers the signals of interest (examples range from the low‑frequency ADA400A and SR850 to microwave amplifiers such as 8349B, 83020A and 83050A); sensitivity vs. dynamic range — low noise figure models are best for weak signals, while higher P1dB and IP3 support larger signals and better linearity; form factor and interfaces — some modules require specific DC bias supplies or system power modules (83050A and 83051A list DC supply options), while others are bench instruments with AC mains (8447D, 8349B); impedance and connector type — preamps and system amps use 50 Ω connectors like 3.5 mm or 2.4 mm, while Tektronix probe/buffer accessories (TCA-1MEG, ADA400A) provide high‑impedance inputs for scopes. Consider maximum safe input power where rated (83051A lists CW survival and pulsed limits) and whether the instrument supplies automated scaling or probe ID for oscilloscope integration (TCA-1MEG supports TekProbe Level 2 automated readout).

Interfaces and control: some amplifiers include instrument interfaces (GPIB, RS‑232) or system hooks for rack integration; others are simple RF front ends with analog connectors only. Connector and cable choices affect return loss and VSWR; use the connector type and impedance specified for the model. Power, cooling and mounting: check the amplifier's power supply requirements and operating temperature before system integration — examples in the catalog include AC mains units (8447D, 8349B) and DC‑powered modules that expect a compatible Keysight supply (83050A, 83051A). For differential or low‑level DC‑coupled measurements, note input resistance and CMRR specifications (ADA400A provides selectable input resistance and high CMRR at 10X/100X gains).