Network Analyzer

Overview
The Network Analyzer is a tool for measuring the frequency response (amplitude and phase characteristics) of equipment and systems. It uses the "Fast Chirp" method (logarithmic chirp signal) to perform high-precision measurements of the entire band in a short time.
Primary uses:
- Measuring frequency response (f-response) of amplifiers and filters.
- Measuring characteristics of speakers and headphones.
- Measuring phase difference and delay between two signals.
Basic Operation
Starting Measurement
- Set the measurement range (Start/End Freq) and Amplitude in the "Settings" tab.
- Adjust the Duration of the chirp signal. Longer durations generally improve the S/N ratio.
- Set the number of Averages. Multiple sweeps are performed and averaged to reduce noise.
- Click the "Start Sweep" button to begin measurement. Progress is shown on the progress bar.
- Click the button again to stop the measurement midway.
Routing and XFER Mode
Input/Output Settings
- Output Ch: Select the channel to output the measurement signal (L, R, or Stereo).
- Input Mode: Select where to receive the signal returning from the measurement target.
- Left (Ch1) / Right (Ch2): Measures the signal of the selected channel. In "Absolute (Level)" mode, it displays the input level in various units.
- XFER (Ref=L, Meas=R): Uses the Left channel as a "reference signal" and the Right channel as a "measurement signal," calculating their ratio (H = Meas / Ref). This allows for measuring pure device characteristics by canceling out the inherent traits of the audio interface (relative measurement).
- XFER (Ref=R, Meas=L): Reverse transfer function mode using Right as reference.
- Crosstalk L -> R / R -> L: Pre-configured macros for measuring crosstalk between channels.
Display and Analysis
Customize the graph display in the "Display" tab.
Graph Types
- Magnitude Response: Displays gain (amplification factor) or absolute level for each frequency. Units can be selected from dBFS, dBV, dBu, Vrms, or Vpeak.
- Phase Response: Displays the phase shift for each frequency.
- Group Delay: Displays the delay time for each frequency, calculated from the slope of the phase (check "Show Group Delay").
- Coherence: Displays the correlation (reliability) between input and output. Values closer to 1.0 indicate high reliability. Low coherence suggests noise, distortion, or timing issues (check "Show Coherence").
Display Options
- Smoothing: Smooths out fine jaggedness (noise) in the graph. Selectable from Off/Light/Medium/Heavy.
- Max/Min Freq: Limits the frequency range displayed on the graph.
- Single-Ch Mode: When using a single input channel, choose between Relative (Gain) (normalized to the output) or Absolute (Level).
Calibration
Latency and IR SNR
- Calibrate Latency: Measures the total input/output delay of the system. This is crucial for accurate phase measurement.
- IR SNR: Displays the Signal-to-Noise Ratio of the Impulse Response for the most recent sweep. Higher values indicate a cleaner measurement.
Reference Trace
Saves the current measurement result as a "reference" to compare with subsequent measurements.
- Store Reference: Saves the current graph as a reference.
- Apply Reference: Subtracts the saved reference from the current measurement result. Useful for checking relative changes or "flattening" a response.
Troubleshooting
- Audio stream failed to start. Check ASIO settings: This error message indicates that the audio stream failed to start. Please verify that the ASIO settings (Sample Rate and Block Size) match your audio interface's configuration.