321

The Sonoma Instrument 321 is a broadband preamplifier covering 9 kHz to 2 GHz (-3 dB), designed for EMI measurements, antenna signal amplification, and general-purpose RF signal amplification applications where high output power and dynamic range are the primary requirements. With a gain of 28.5 ±1.5 dB at 1 GHz, gain flatness of 1.0 dB from 100 kHz to 1.6 GHz, and a third order intercept point of +33 dBm, it delivers the linearity and output headroom needed for demanding measurement scenarios where strong and weak signals must be handled simultaneously without intermodulation distortion compromising accuracy.

Key specifications include an output at 1 dB gain compression of +20 dBm from 100 kHz to 1.8 GHz (+17 dBm from 1.8 to 2 GHz), a noise figure of 6.5 dB from 10 MHz to 2 GHz, harmonic distortion of -30 dBc at +20 dBm output, and 40 dB of reverse isolation from 100 kHz to 2 GHz. Input and output return loss are both 10 dB from 100 kHz to 2 GHz. The equivalent input noise voltage is 0.95 nV/√Hz from 10 MHz to 2 GHz including noise from a 50 Ω source. The maximum input for linear operation is approximately -8.5 dBm (84 mV rms), with an input damage level of +10 dBm / ±1V — significantly more robust than the Sonoma 310 and 315. The unit is AC coupled with 50 Ω impedance and uses Type N female connectors at both input and output.

Time domain performance includes a typical transition time of 140 psec and group delay of 790 ±50 psec from 1 MHz to 2 GHz. The unit is mains-powered at 100, 120, 220, or 240V AC / 50–60 Hz at 20 VA via an IEC 60320 C13 power cord. Operating temperature range is 0 to +45°C up to an altitude of 15,240 ft / 5,000 m. Physical dimensions are 91 × 109 × 183 mm (H × W × D) — identical in form factor to the Sonoma 310 and 315 — with a net weight of 1.5 kg.