Exercises for FMCW

The FMCW base-module is a real, low power FMCW & Doppler radar, optimized for close range applications. There are countless possibilities for exercises.
Based on target group, educational concept and learning outcomes, the exercises and their conception will be varying.

Here we suggest a sequence of exercises which can make sense:

Range Resolution

Demonstrating the relationship between modulation and range resolution. Caused by the fixed number of range cells increasing the dimension of the resolution cell increases as well the unambiguous range. But the transmitted power is limited – the real maximum range depends on the conditions of the fundamental radar equation. Thus there are two independent limitations in radar: the pulse period and the energetic conditions.

Learning Outcome

• Learners will be able to understand and interpret the relation modulation and range resolution.
• Learners will be able to identify the most suitable range calibration to receive the best image.
• Learners will be able to understand and interpret the results indicated in the different scopes.

Saw Tool Modulation and Effect

An FMCW radar can be modulated with different wave-forms. Every waveform has got its own advantages and disadvantages

In saw tooth modulation you can measure the distance in a long range. The slope of the ramp is variable. It can be shown the relationship between steepness of the slope, the range resolution and maximum unambiguous range. In this mode the measurement of speed isn’t possible.

The Doppler frequency causes a measurement error only.

Learning Outcome

• Learners will be able to understand and interpret the relation between steepness of the slope, the range resolution and maximum unambiguous range.
• Learns will be able to conduct a measurement with saw tooth modulation and calibrate the scopes to achieve a reasonably good measurement result.
• Learners will be able to describe and explain the advantages of saw tooth modulation.
• Learners will be able to understand and interpret the results indicated in the different scopes.

Range and Speed

Range and Speed can be measured simultaneously using the triangle form of frequency modulation with an additional direct current part, but it requires double the time for the same steepness of the slopes.

Learning Outcome

• Learns will be able to conduct a measurement with the triangle form of frequency modulation and calibrate the scopes to achieve a reasonably good measurement result.
• Learners will be able to describe and explain the advantages of the triangle form of frequency modulation.
• Learners will be able to measure range and speed simultaneously with the triangle form of frequency modulation.
• Learners will be able to understand and interpret the results indicated in the different scopes

Frequency Shift Keying

The mode Frequency Shift keying is the most accurate measurement of the distance. But it works in very short distances and for a single reflecting object only.

Learning Outcome

• Learns will be able to conduct a measurement with the FSK form of frequency modulation and calibrate the scopes to achieve a reasonably good measurement result.
• Learners will be able to describe and explain the advantages of the FSK form of frequency modulation.
• Learners will be able to measure single reflecting objects in short distances with the FSK form of frequency modulation.
• Learners will be able to understand and interpret the results indicated in the different scopes