Simrad SP90

Simrad SP90RCG (Reverberation Controlled Gain)The RCG filter senses the noise level (reverberation, propellernoise, etc.), and adjusts the gain individually for each of the 64receiver beams in order to eliminate noise on the display. Thestrength of the filter can be selected in the menu. With maximumstrenght is selected, the RCG will effectively reduce the bottom inshallow water, while variations on the bottom will be displayed.Note that scattered fish can be perceived as reverberation. TheRCG filter must therefore be used with care if scattered schools areto be detected.PP FilterThe SP90 sonar is equipped with a ping-to-ping filter to give aclean and steady presentation by reducing the interference andnoise. This filter compares the echoes from a selected amount oftransmissions (pings), and an echo has to be present in the selectedamount of pings in order to be presented on the display.Note that in rough seas, when the beam easily can miss the targetin several pings, the PP filter must be used with care.TVG (Time Variable Gain)The TVG function controls the gain of the receiver so that a schoolwith a given size and density is presented with approximately thesame strength on the display, inside the regulated TVG range. Thiscan also be seen as a filter, because it reduces the noise close to thevessel.The regulated strength of the TVG can be selected in the menu.TransmissionThe transmitting is controlled by the signal processor in theTransceiver Unit. The parameters you have chosen are used.There are 256 separate transmitters in the unit distributed on eighttransceiver circuit boards. Each transmitter is individuallyaddressed and controlled from the signal processor. The controlledparameters include power output and time delay for eachtransducer element in order to form a beam with the selected tiltangle.10 850-164511 / B