From what I comprehend in PD modes the DDD shows only closure, the aspect switch changes closure scale. I haven’t found much use of this as most interceptions are within 1000 knots of closure and are within the normal “ aspect “ range, with exception of say trying to intercept a cruise missile going Mach 10 then the aspect switch would be used to adjust closure scale.
This applies to all the Doppler modes PD search RWS TWS and PDSTT.
As far as Pulse modes goes I have found it to be unreliable at best, failing to show contacts despite the IFF getting returns and displaying the returns on the DDD.
Also note the aspect switch in pulse mode directs the AWG9 to focus on the leading edge of the target ie. nose. Etc. And the DDD now displays range only which is scaled with the range select buttons above the DDD
