|
|
Posts: 32916
Location: Rhinelander, Wisconsin | 'An LCD (liquid-crystal display) like a computer, is a digital device. Manufacturers are increasingly putting both an analog and a digital connection on LCDs. When connected via an analog connection, an LCD is vulnerable to the same distortions that affect CRT monitors. However, when connected via a digital connection, often labeled DVI (for Digital Visual Interface), no digital-to-analog conversion is required, and there should be no loss or corruption of the signal. '
I think this is the premise of the claims above in some of the posts. See why I'm asking the question? I agree it would seem odd to convert and then convert back....will make that call Monday. |
|
| |
|
Posts: 720
| Steve here is a little bit of an article I read. Maybe it can answer some of your conversion questions. Honestly, this conversation is getting to far over my head and I must go lie down now:
Sonar by its very nature uses an "analog" sound wave that is transmitted into the water by the fishfinder transmitter. These sound waves travel into the water on a carrier frequency such as 200kHz. These sound waves echo off the bottom, fish, and structure creating many varying sonar echoes that return back to the receiver on the analog frequency. This analog signal is then converted to digital within the fishfinder by virtually all marine electronics companies - the differences lie in what point within the sonar system the conversion takes place. Those promoting "digital" sonar convert these analog signals to digital within a sonar receiver itself. Humminbird converts analog signals using the analog to digital capability of the on-board microprocessor. Therefore, Humminbird offers digital technology, however the conversion from analog to digital just occurs differently that what is being promoted by others. It is interesting to note that Humminbird has been converting analog to digital in this manner since 1989.
Further benefits of units marketed as "digital" sonar include technology such as adaptive transmitters, and "virtually" infinite variable bandwidths. It is important for the consumer to know that these benefits are not limited to the methodology of the so called "digital" sonar products. If fact these and other techniques are central to Humminbird's Professional Grade Sonar. Humminbird transmitter design offers adaptive technology that modulates power and pulse width based on conditions.
Additionally, Humminbird's receiver offers variable bandwidth and wide 90db dynamic range to hear both high and low intensity signals simultaneously. Another key benefit touted by marketers of "digital" sonar is the use of filtering algorithms in their design to remove unwanted noise and clutter. The use of filtering techniques produces results counter to the desires of all anglers, since these "intelligent" algorithms actually remove information that is important to the angler - such as detail in structure and fish.
I don't know if that helps or not. Just trying to contribute.
Edited by Hunter4 8/28/2010 10:38 PM
|
|
| |
|
Posts: 233
Location: Iowa | firstsixfeet,
I don't use it up front at all either. I usually depend on regular sonar and gps when I'm up front. I just think it is a unique feature over h-bird.
I also understand your point on the total compactness idea. But I also like the idea of having two seperate transducers better.
I agree with you on the whole technology stuff. Most of it is way over my head too. I just repeat alot of what I have read and gather from other people.
Either way you go, you won't be sorry you spent the money on structure scan or side imaging. One more word of advice, get the biggest screen you can afford. If I were you I wouldn't waste your money on the 5" units. When I original was going to buy my units I was going to get a HDS 5 and HDS 8. But after looking them many times and some advice from others, I went with a 10 and a 7. It was well worth it.
If you have any questions, feel free to pm me. I'm heading to leech this next week and will try to capture some screen shots. When I get home I can post a few of them.
Jeremy
Edited by jwelch 8/28/2010 11:13 PM
|
|
| |
|
| Esox Maniac gave a good explanation. The LCD display itself is a digital device. The transducer/receiver is analog. The analog sonar information needs to go through A/D conversion for display. There can be a small amount of loss or distortion during the a/d conversion process. Resolution and accuracy will depend on the bit depth of the converter. Regardless of whether the input is digital or analog, the output needs to be digital for an LCD display. Analog input requires conversion, digital does not assuming the display can handle the input resolution. Sorry for my rather simplistic original post. |
|
| |
|
| Everyone should remember is that digital signals are completely artificial. Humans themselves are capable of only taking in information in an analog format, and every piece of information in this world is generated in an analog format. The only reason to ever transfer to digital is digital signals are far easier to maintain and process. You do lose some information whenever to perform an ATD conversion and also some when you perform a DTA. The world would have you convinced that digital always means better, but that isn't necessarily the case. In regards to these sonars, they are remarkably similar. It wouldn't surprise me at all if the displays for both Humminbird and Lowrance were provided by the same company. |
|
| |
