The Agilent / HP 3585A Spectrum Analyzer delivers high performance where it counts - at baseband frequencies. With unmatched accuracy, resolution, and dynamic range, the 3585A is HP's best solution for signal analysis at the critical frequencies comprising voice, picture, or digital information.

In today's high speed, high density information processing systems, maintaining the integrity of data signals requires more measurement performance than ever before. The 3585A provides 80 dB of spurious-free dynamic range, a sharp 3 Hz resolution bandwidth, and fully synthesized tuning. Its 20 Hz - 40.1 MHz frequency range is more than adequate to cover most information bandwidths.

Measurement performance is critically important at baseband frequencies, because signal degradation occurring here is typically not recoverable elsewhere in the system. As a result, test requirements for baseband signals and circuits often demand a level of performance that only a high-performance, low-frequency signal analyzer such as the HP 3585A can provide.

The HP 3585A is a swept hetrodyne, triple conversion circuit with several major improvements. Frequency tuning is accomplished by a fully synthesized, phase continuous local oscillator, assuring excellent frequency stability for narrowband analysis across the entire frequency range. Internal microprocessors manage several functions including front panel operation, 1001-point digital vector storage display, and periodic calibration of amplitude and frequency offsets. An accurate internal narrowband frequency counter can discriminate between the frequencies of closely spaced sinusoids with 0.1 Hz resolution. Finally, the HP 3585A contains fast-settling narrow resolution bandwidth filters that are among the best in the industry.

Well-designed filters and the phase-continuous, synthesized local oscillator team up to give the HP 3585A very fast sweep speeds. A 40-MHz sweep using the 30-kHz resolution bandwidth takes only 200 milliseconds, fast enough for high-resolution spectrum surveillance. A 1-MHz sweep using a 1-kHz bandwidth takes only 2 seconds.

Sweep width can be set to any arbitrary span between 0 and 40.1 MHz, or adjusted from 100 Hz to 40 MHz in a 1,2,5 step format. Resolution bandwidth and sweep time automatically track the selected frequency span to ensure optimum performance, or can be manually controlled.

The high performance of the HP 3585A is further complimented by a built-in 1001 X 1024-point display. Measured analog signals are converted to 1001 digital data points prior to storage and display, allowing each point to be accessed individually using the display marker.

The HP 3585A's microprocessor-controlled front panel and CRT readout simplify complicated measurements. Frequency and amplitude settings may be entered directly using the keypad, incrementally stepped, or varied continuously using the rotary pulse generator.

An autoranging input attenuator eliminates the task of manually adjusting attenuation to achieve the correct mixer level. The input Range can also be manually adjusted from -25 dBm to +30 dBm in 5-dB steps.

With its primary marker set to a signal peak or other point of interest, the HP 3585A displays amplitude and frequency numerically on the CRT. A second marker numerically displays amplitude and frequency offsets between two markers. Programmable Offset Step allows an operator to move easily between harmonically-related signals or evenly-spaced communication channels.

Quiet and rock-stable, the HP 3585A excels as a noise and distortion analyzer. Its own uncompromising sensitivity and spectral purity are assured by its advanced front end design, synthesized local oscillator and built-in, oven-stabilized reference.

The HP 3585A can measure spurious, harmonic, and intermodulation products at levels typically 100 dB or more below the fundamental. Using its 3 Hz resolution bandwidth, power line sidebands below -95 dBc can typically be measured at frequency offsets of only 50 or 60 Hz. Total harmonic distortion and intermodulation distortion measurements can be automated using HPIB programming.

A built-in noise level key displays RMS noise density normalized to a 1 Hz bandwidth at the marker position, allowing easy comparison of measurements made with different resolution bandwidths.

With its built-in tracking generator, digital trace storage, and narrowband frequency counter, the HP 3585A Spectrum Analyzer can accurately measure the frequency response of crystals, filters, and amplifiers. Small amplitude variations are resolved to 0.01 dB using the marker readout and the 1 dB/division expanded amplitude scale. Unwanted effects of test fixtures and cables are removed simply by storing the frequency response of the test setup in Trace B and subtracting it from measured data in Trace A.

With its wide dynamic range capability and high-resolution display, the HP 3585A is ideal for measuring and viewing the analog portions of 14 or 16-bit digital audio systems. It can also measure the frequency response of digital modem filters with better than ± 0.4 dB accuracy.

In addition to its many uses as a baseband signal analyzer, the HP 3585A finds a home in HF radio applications as well. Synthesized tuning and high-resolution display make wideband surveillance of the entire 30-MHz radio spectrum easy. Fast-settling resolution bandwidth filters speed the analysis of modulated HF carriers.