The HP 8901A Modulation Analyzer is an outstanding signal characterization product with a frequency range of 150 kHz to 1300 MHz. It combines all the necessary capabilities for accurate transmitter measurements, including carrier power, carrier frequency and stability, AM depth, FM deviation, hum and noise, incidental AM or FM, modulation limiting (instantaneous and steady state), and audio frequency response. It can also be used to test modules and subassemblies from either the transmitter or receiver. The modulation analyzer features input power protection to reduce the risk of accidental damage when connected directly to a high power transmitter.
The HP 8901A Modulation Analyzer is a laboratory instrument that measures carrier frequency, peak power, and modulation characteristics across a 150 kHz to 1300 MHz range. It combines functions of a frequency counter, power meter, and modulation meter, offering automatic tuning, single‑key operation, and programmable remote control via HP‑IB.
The manual describes the analyzer’s measurement capabilities (AM, FM, PM, RF power), special functions such as auto‑tune‑track, post‑detection audio filters, and built‑in calibrators. It also lists optional accessories, warranty information, and service procedures.
| Frequency Range | 150 kHz to 1300 MHz |
|---|---|
| Frequency Resolution | 10 Hz below 1000 MHz, 100 Hz above 1000 MHz |
| Input Level (Automatic Mode) | –20 dBm to +30 dBm |
| Input Level (Manual Mode) | –60 dBm to +30 dBm |
| Power Display Range | 1 mW to 1 W |
| Power Accuracy | Typically +1.5 dB |
| Input Power Protection | >25 W |
| AM Rate Range | 20 Hz to 100 kHz |
| AM Depth | up to 99 % |
| AM Accuracy | +1 % of reading +1 digit (rates 50 Hz‑50 kHz, depths >5 %) |
| FM Rate Range | 20 Hz to 200 kHz |
| FM Deviation | up to 400 kHz |
| FM Accuracy | +1 % of reading +1 digit (rates 30 Hz‑100 kHz) |
| Phase Modulation Rate Range | 200 Hz to 20 kHz |
| Phase Deviation | up to 400 radians |
| Phase Accuracy | +3 % of reading +1 digit |
| Sensitivity | -25 dBm (12 mVrms) below 650 MHz, –20 dBm (22 mVrms) above 650 MHz |
| Dynamic Range | >50 dB (22 mVrms to 7 Vrms) |
| Residual AM Noise | <0.02 % rms (50 Hz‑3 kHz bandwidth) |
| Residual FM Noise | <8 Hz at 1800 MHz, <1 Hz below 100 MHz |
It measures signals from 150 kHz up to 1300 MHz.
AM depth is measured with better than 1 % of reading accuracy, with +1 digit for rates 50 Hz‑50 kHz and depths greater than 5 %.
The instrument includes protection for input powers greater than 25 W using limiting diodes and an RF relay.
Yes, it is fully programmable via the Hewlett‑Packard Interface Bus (HP‑IB).