What are the advantages and disadvantages of digital simulators and fiber optic simulators?

What are the advantages and disadvantages of digital simulators and fiber optic simulators?

1) The digital simulator has small distance steps and high accuracy, and the step and accuracy can reach 1mm;

The fiber optic simulator can only achieve 1cm step and accuracy.

2) The inherent delay of the digital simulator is larger than that of the optical fiber simulator, but through the compensation algorithm, distance simulation close to zero meters can be achieved (both the Airgap and external radio frequency length can be compensated);

The inherent delay of fiber optic simulator is small and can generally be simulated to 2m (excluding Airgap and external RF cable length).

3) The digital simulator can simulate long-distance targets of hundreds of kilometers with almost no additional hardware.

Fiber optic simulators need to add cascade switches to simulate long distances, which are generally only a few kilometers away.

4) In a single channel, the digital simulator can achieve multi-objective simulation at very low hardware cost;

The optical fiber simulator performs two target simulations in a single channel, and the hardware cost almost needs to increase exponentially.

5) The digital simulator hardware has an ADC and FPGA inside, so additional instrumentation functions such as signal sources, interference sources, and spectrum analyzers can be integrated in the simulator through software;

Fiber optic simulators do not have this hardware advantage and require additional configuration of corresponding instruments to obtain relevant data.

6) The digital simulator has an amplitude compensation function, so the flatness index value can be better.

7) The optical fiber simulator has the advantage of large bandwidth and can reach the instantaneous bandwidth of 5G. The current maximum instantaneous bandwidth of the digital simulator can reach 2GHz, and it can reach 3GHz or 4GHz through hardware upgrade.

8) The digital simulator implements close-range simulation through a compensation algorithm, so the noise of close-range targets is slightly higher than that of the optical fiber simulator (about 5dB), which generally does not affect the use.

9) Digital simulators cannot simulate pulse compression system radar at close range, and fiber optic simulators do not have this limitation. However, considering the low cost in the field of automotive radar, they are basically FMCW waveforms and do not use pulse pressure systems, so digital simulators can be used.