Agilent / HP 3585A

• 0.1 Hz Resolution
• 3 Hz Resolution Bandwidth
• -137 dBm to +30 dBm Measurement Range
• 50 Ohm, 75 Ohm, and 1 Mohm Selectable Input Impedance
• Built-in Tracking Generator
• Autoranging Input Attenuator
• Readout on CRT of panel settings & markers
• 1001 X 1024 Digital Storage Display
• HP-IB Interface
• 80 dB dynamic range
• ± 0.4 dB Amplitude Accuracy

Uncompromising Baseband Signal Analysis
The 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.


Inside the HP 3585A
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.

Fast, Flexible Frequency Sweeps
Well-designed resolution bandwidth filters and a phase-continuous, synthesized local oscillator team up with exceptional dynamic range to give the HP 3585B very fast measurement 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 seep using a 1 kHz bandwidth takes only 2 seconds, yet yields an average noise floor of -85 dBc.

Powerful Marker Functions
The turntable marker readout of frequency and amplitude can display an absolute or relative (offset) value.  With a single keystroke, enter the marker value as the center frequency, reference level, frequency span, or center frequency step size.  This improves accuracy and efficiency in manual testing and reduces setup errors.
The built-in frequency counter provides additional accuracy when measuring the frequency of a signal in the display.  It provides results in 0.3 seconds to 0.1Hz resolution.  Because the counter function is combined with the selectivity of the analyzer, it is possible to accurately measure small signals in the vicinity of much larger ones.