Choose a signal, spectrum, or wireless analyzer by matching the instrument’s frequency coverage, analysis bandwidth, sensitivity, dynamic range, phase noise, portability, and software capabilities to your measurement task.

Start with these application requirements:

• Signal frequency: Select an analyzer that covers your carrier frequency,
  harmonics, and spurious search range.
• Analysis bandwidth: Use wider bandwidth for 5G NR, Wi-Fi 7, radar pulses,
  satellite links, and wideband modulation analysis.
• Sensitivity: Look for low DANL when detecting weak signals or emissions close
  to the noise floor.
• Dynamic range: Choose higher dynamic range when measuring low-level spurs near
  high-power carriers.
• Phase noise: Prioritize low phase noise for oscillator, radar, satellite,
  aerospace, and high-performance wireless testing.
• Form factor: Use benchtop analyzers for R&D, handheld analyzers for field
  RF testing, wireless analyzers for protocol and network troubleshooting, and modular
  PXIe analyzers for automated test systems.

Keysight offers Essential, Expert, and Pro benchtop signal and spectrum analyzers that can be selected based on maximum frequency, analysis bandwidth, phase noise, DANL, and real-time spectrum analysis capability.

Key specifications for a signal, spectrum, or wireless analyzer include frequency range, resolution bandwidth, analysis bandwidth, dynamic range, DANL, phase noise, amplitude accuracy, real-time bandwidth, and measurement software support.

Important specifications include:

• Frequency range: Defines the lowest and highest frequencies the analyzer can
  measure.
• Resolution bandwidth, or RBW: Determines how well the analyzer separates
  closely spaced signals. Narrow RBW improves frequency resolution and lowers displayed
  noise, while wider RBW enables faster sweeps.
• Analysis bandwidth: Defines the instantaneous bandwidth available for
  demodulation, vector signal analysis, and wideband capture.
• Dynamic range: Determines how well the analyzer can measure weak signals in the
  presence of stronger signals.
• DANL: Displayed average noise level indicates analyzer sensitivity. Lower DANL
  improves weak-signal detection.
• Phase noise: Indicates short-term frequency stability, typically specified in
  dBc/Hz at a defined carrier frequency and offset.
• Real-time spectrum analysis, or RTSA: Helps capture intermittent, transient,
  pulsed, or frequency-hopping signals that may be missed by swept measurements.
• Measurement applications: Consider support for EVM, ACPR, occupied bandwidth,
  spurious emissions, EMI pre-compliance, pulse analysis, noise figure, and wireless
  standards.

A spectrum analyzer measures signal power versus frequency. A vector signal analyzer measures both magnitude and phase to analyze digitally modulated signals. A real-time spectrum analyzer continuously captures spectrum activity to detect short-duration or intermittent RF events.

• Spectrum analyzer: Best for frequency-domain measurements such as harmonics,
  spurious emissions, occupied bandwidth, carrier power, channel power, and EMI
  troubleshooting.
• Vector signal analyzer: Best for modulation quality measurements such as IQ
  constellation, error vector magnitude, OFDM analysis, and demodulation of standards such
  as 5G NR, LTE, Wi-Fi, and satellite waveforms.
• Real-time spectrum analyzer, or RTSA: Best for capturing transient events such
  as pulsed radar, frequency hopping, burst interference, wireless coexistence problems,
  and intermittent field interference.

Keysight signal and spectrum analyzer workflows can support spectrum analysis, vector signal analysis, real-time spectrum analysis, and software-driven measurements for wireless, aerospace / defense, EMI, and phase-noise applications.

A signal analyzer is primarily used for frequency-domain analysis, while an oscilloscope is primarily used for time-domain analysis.

A signal analyzer displays how power is distributed across frequency. Engineers use it to measure RF characteristics such as carrier frequency, signal amplitude, phase noise, harmonics, occupied bandwidth, spurious emissions, and interference.

An oscilloscope displays how voltage changes over time. Engineers use it to view waveform shape, timing, rise time, jitter, transients, digital switching behavior, and circuit-level events.

In practice:

• Use a signal analyzer for RF, microwave, wireless, modulation, and spectrum
  measurements.
• Use an oscilloscope for time-domain waveform, digital, analog, and high-speed timing
  measurements.
• Use both instruments when debugging complex systems that require time-domain and
  frequency-domain visibility.