I hardly could wait to have this receiver on my table. The NRD-545 DSP can only be compared to its older brothers with difficulty.
The operation is as usual. Anyone who has owned a NRD will be familiar with it quickly. But as far as the bandwidth filters and the audio are concerned, you have to orientate yourself anew. The bandwidth filters are unusually steep so that you have to turn the tuning knob slowly otherwise you end up on the wrong frequency. As far as selectivity is concerned, the NRD-545 DSP is absolutely top class. The bandwidths can be controlled continuously from 40Hz to 9.99 KHz, either in 10Hz increments or in 100Hz steps. The notch filter and pass band tuning are also digitally generated and extremely effective. There is also a digital notch filter and noise blanker. Unfortunately, the noise filter does not work very well. It produced digital artifacts and even made the signal more difficult to read. The sound of the NRD-545DP requires some getting used to. In AM it sounds rather sharp and aggressive. Additionally, the receiver makes noise, when no signal is present. As soon as there is a weak signal, the noise disappears into the background and the signal is like punched out from the noise. The readability is even better in SSB.
The large signal rejection of the NRD-545 is worse than the one of the previous models. That has to do with the DSP. The radio does not tolerate strong signals. Active antennas, e.g., the ARA60, are not suitable. You are far better off with a passive long wire. With a converter board, the range of the NRD-545DSP can be extended to 2000MHz. This board cannot be recommend unconditionally because it is badly suited for the upper frequencies and far too expensive. You do a lot better with a scanner.
Anyone who listens more to AM-broadcasts should listen to the NRD-545 first before buying one. This is very important to avoid a bad buy especially because the receiver is not cheap.
The NRD-545 DSP is mainly for SSB listeners because in this mode it offers the whole range of options. For AM it can only be recommended with reservations. First of a all, an adjustable AGC!!