1. Pre-Test Preparation

1. Equipment and Tool Preparation
   • The frequency converter to be tested (including input/output interfaces, power interfaces, etc.)
   • A signal source (e.g., function generator, RF signal source) to provide input signals
   • A spectrum analyzer/oscilloscope to measure output signal frequency, amplitude, distortion, etc.
   • A power meter for measuring input/output power
   • A power supply matching the device’s rated voltage/current (DC or AC)
   • Connection cables (coaxial cables, signal cables, etc.) and attenuators (to prevent damage from high-power signals)
   • A temperature/humidity meter and cooling equipment (to simulate different environmental conditions)
2. Parameter Verification
   Clarify the device’s rated parameters: input frequency range, output frequency range, conversion gain (or attenuation), noise figure, nonlinear distortion (e.g., intermodulation distortion), rated power, operating temperature range, etc., as testing benchmarks.

2. Basic Function Testing

1. Power-On and Initialization Testing

• Connect the power supply according to the manual, confirm no abnormal heating or noise, and ensure indicator lights/displays start normally.
• Verify the device can enter normal operating mode (e.g., via buttons or software configuration to switch between up-conversion and down-conversion modes).

2. Frequency Conversion Function Verification

• Down-Conversion Test:
  1. Use a signal source to output a high-frequency signal (e.g., an RF signal within the device’s rated input range, such as 1GHz).
  2. Connect the signal to the converter’s “down-conversion input” port, set the device to down-conversion mode, and specify the target output frequency (e.g., 70MHz intermediate frequency).
  3. Use a spectrum analyzer to monitor the “down-conversion output” port. Confirm the output frequency matches the target (70MHz) with deviations within the allowable range (typically ±1kHz or smaller, depending on device accuracy).
• Up-Conversion Test:
  1. Use a signal source to output a low-frequency signal (e.g., 70MHz intermediate frequency) and connect it to the converter’s “up-conversion input” port.
  2. Set the device to up-conversion mode and specify the target output frequency (e.g., 1GHz).
  3. Use a spectrum analyzer to test the “up-conversion output” port. Confirm the output frequency matches the target (1GHz) and that frequency deviation meets requirements.

3. Performance Metrics Testing

1. Gain/Attenuation Testing

• Test the converter’s ability to amplify or attenuate signal amplitude:
  1. Output a fixed-amplitude input signal (e.g., -30dBm) from the signal source, and record the input power (measured with a power meter).
  2. Measure the output signal power at the output port using a power meter or spectrum analyzer.
  3. Calculate the gain (output power minus input power) and compare it with the device’s rated gain. The deviation should be ≤±1dB (specific to device specifications).
  4. Adjust the input signal frequency within the rated range and repeat tests to confirm gain consistency (flatness).

2. Noise Figure Test

• Measure the extent to which the converter introduces noise into the signal (especially critical for down-converters in receiving chains):
  1. Connect a noise figure tester to the device’s input and output terminals.
  2. Test the noise figure at different frequency points within the device’s operating range. It should be ≤ the rated value (e.g., ≤5dB).

3. Nonlinear Distortion Test

• Detect signal distortion caused by the converter’s nonlinear characteristics (e.g., harmonics, intermodulation distortion):
  • Harmonic distortion: Input a single-frequency signal (e.g., f0) and use a spectrum analyzer at the output to check for harmonics (2f0, 3f0, etc.). The harmonic suppression ratio (ratio of harmonic power to fundamental power) should be ≥60dBc (depending on device requirements).
  • Intermodulation distortion: Input two signals of different frequencies (e.g., f1, f2) and check for intermodulation products (e.g., 2f1-f2, 2f2-f1) at the output. The intermodulation suppression ratio should be ≥50dBc (depending on device grade).

4. Dynamic Range Test

• Determine the input power range within which the converter operates normally:
  1. Adjust input power from low to high, and record the minimum input power (sensitivity) and maximum input power (overload point) where output signal distortion remains insignificant (e.g., gain deviation ≤3dB, harmonic suppression meets standards).
  2. The dynamic range (maximum input power minus minimum input power) should meet the rated value (e.g., ≥60dB).

4. Stability and Environmental Adaptability Testing

1. Long-Term Operational Stability
   • Operate the device continuously under rated conditions (e.g., 24 hours). Periodically record output frequency, gain, noise, and other parameters, and check for drift (e.g., frequency drift ≤±5kHz, gain drift ≤±0.5dB).
2. Temperature Adaptability Testing
   • Simulate extreme temperatures in a high/low-temperature chamber (e.g., -20°C to +60°C, within the device’s operating range). Test whether frequency conversion functionality and gain stability meet standards under these conditions.
3. Power Supply Fluctuation Test
   • Adjust the supply voltage to fluctuate within ±10% of the rated range (e.g., 200V to 240V for a nominal 220V AC supply). Verify the device operates normally and output parameters remain stable.

5. Interface and Control Testing

• Communication Interface Testing: If the device supports remote control (e.g., via RS485, Ethernet, or GPIB), send control commands (e.g., mode switching, frequency adjustment) from a host computer. Verify command responses are accurate and latency is within acceptable limits.
• Protection Function Testing: Simulate abnormal conditions (e.g., overcurrent, overvoltage, input signal overload) and check if the device triggers protective mechanisms (e.g., automatic shutdown, alarms) and resumes normal operation after the fault is resolved.

6. Test Report Compilation