The HSA-X series high-speed, fixed-gain, low-noise preamplifiers from Femto Messtechnik GmbH are available in three standard versions that feature different bandwidths and gain. All use standard 50-(omega) input and output impedance that results in a voltage standing-wave ratio from <1.5 to 2 GHz. Specifications include gain of 20/40 dB, bandwidths from 10 kHz to 1.5 GHz at –3 dB and gain flatness better than 0.3 dB. The amplifiers deliver 11-dBm output and exhibit a 50-(omega) noise figure from 1.9 to 5.1 dB. They have a bias coil in the DC path of the input circuitry and are encased in a compact EMI-shielded housing that measures 54 x 43 x 22 mm. Input and output signal terminals use SMA-type jacks. Applications include time-resolved pulse and transient measurements. The devices also can be used as preamplifiers for ultrafast detectors.