A
Anonymous
Guest
There has been a lot of confusion about the number of frequencies for different detectors. There really is no need for the confusion as the detection depth, discrimination, and operation of the Explorer speaks for itself.
<STRONG>However, if one is inclined to understand the more technical working then I would suggest a serious look at several Minelab patents to get a better understanding.</STRONG>
<span style="background-color:#ffff00;">We can however create a basic model that all us can relate to.</span> While not 100% correct it is more than enough to understand what is going on and is easy for anyone to understand.
Consider a body of water such as in a plastic pool that we use for little kids to play in. If we drop a round metal ball in the center of the water we will see rings that start at the point of impact and spread out to the edges of the water. We have to ignore the waves that bounce off the sides of the enclosure for this model. If we drop the metal ball from the same height we will count the same number of waves that radiate from the point of drop. Unless we do something to stop that wave action it will be repetitive.
We can think of the metal ball as the transmit coil power from the detector and the waves that we count as the frequency of energy imparted to the soil. The water represent sthe the soil IF we count the nuber of waves then we look at this from a frequncy domain or FD point of view. However, we can focus on a single wave, as an example, as it starts at the point of impact and travels outward to the edges and measure the time it takes to travel from on point to another. Now we are looking at the wave or waves from a time domain point of view.
Now consider an object being placed in the water at some distance from the point of impact so that the waves will strike the object. We can try to predict what the object is that causes the waves to be distorted. We can look at just one wave and use a time domain analysis or look at all the waves from a frequency point of view. We can look at every other wave as a sampling technique and try to understand what the object that the waves struck is from that analysis.
Here is the bottom line.<span style="background-color:#ffff00;"> The waves are there no matter which method we use just as there are 28 frequencies in the transmission of the energy into the soil.</span> They are in fact there no matter what we read or hear. But, on the analysis side of the house it is a question of do we focus on the number of waves or the time of a wave to help us determine what an target is in the volume of soil. Now add this and we have a model I think we can all work with and that is do we look at a single wave, all the waves, or sample every other wave, three or four of the waves for comparison purposes. If we are primarily interested in analyzing the frequency of the waves then we design for that purpose, if the time of a wave then the design is for that purpose and lastly if we sample different waves at some specific rate then for that purpose.
<span style="background-color:#ffff00;">There are 28 frequencies and the sample rate is confused by many as being the frequency of operation.</span> I find some interesting numbers in that three-sample rate and 10 channels is 30. Fix the bottom and top frequency and subtract 2 from 30 and you have 28. Don't make anything out of this as the real heart of the matter is in the shifting of the spectrum by noise cancel in conjunction with the sample rate. I just threw this last paragraph in as I have broken down and am taking a serious look at about 4 patents that explain how all this is done. Glenn they do have one those in particular deals with obtaining the best SNR, which I found interesting as I had given up on my theory about that.
<span style="background-color:#ffff00;">Let me sum this up by saying we get all 28 frequencies we paid for and they do have various options as to how select and use them in a time domain application in the receiver. The myth about three or four transmitted frequency is just that a myth. Give me a while to study all the patents as it takes a lot of time to go through all of the patents.</span>
HH, Cody
<STRONG>However, if one is inclined to understand the more technical working then I would suggest a serious look at several Minelab patents to get a better understanding.</STRONG>
<span style="background-color:#ffff00;">We can however create a basic model that all us can relate to.</span> While not 100% correct it is more than enough to understand what is going on and is easy for anyone to understand.
Consider a body of water such as in a plastic pool that we use for little kids to play in. If we drop a round metal ball in the center of the water we will see rings that start at the point of impact and spread out to the edges of the water. We have to ignore the waves that bounce off the sides of the enclosure for this model. If we drop the metal ball from the same height we will count the same number of waves that radiate from the point of drop. Unless we do something to stop that wave action it will be repetitive.
We can think of the metal ball as the transmit coil power from the detector and the waves that we count as the frequency of energy imparted to the soil. The water represent sthe the soil IF we count the nuber of waves then we look at this from a frequncy domain or FD point of view. However, we can focus on a single wave, as an example, as it starts at the point of impact and travels outward to the edges and measure the time it takes to travel from on point to another. Now we are looking at the wave or waves from a time domain point of view.
Now consider an object being placed in the water at some distance from the point of impact so that the waves will strike the object. We can try to predict what the object is that causes the waves to be distorted. We can look at just one wave and use a time domain analysis or look at all the waves from a frequency point of view. We can look at every other wave as a sampling technique and try to understand what the object that the waves struck is from that analysis.
Here is the bottom line.<span style="background-color:#ffff00;"> The waves are there no matter which method we use just as there are 28 frequencies in the transmission of the energy into the soil.</span> They are in fact there no matter what we read or hear. But, on the analysis side of the house it is a question of do we focus on the number of waves or the time of a wave to help us determine what an target is in the volume of soil. Now add this and we have a model I think we can all work with and that is do we look at a single wave, all the waves, or sample every other wave, three or four of the waves for comparison purposes. If we are primarily interested in analyzing the frequency of the waves then we design for that purpose, if the time of a wave then the design is for that purpose and lastly if we sample different waves at some specific rate then for that purpose.
<span style="background-color:#ffff00;">There are 28 frequencies and the sample rate is confused by many as being the frequency of operation.</span> I find some interesting numbers in that three-sample rate and 10 channels is 30. Fix the bottom and top frequency and subtract 2 from 30 and you have 28. Don't make anything out of this as the real heart of the matter is in the shifting of the spectrum by noise cancel in conjunction with the sample rate. I just threw this last paragraph in as I have broken down and am taking a serious look at about 4 patents that explain how all this is done. Glenn they do have one those in particular deals with obtaining the best SNR, which I found interesting as I had given up on my theory about that.
<span style="background-color:#ffff00;">Let me sum this up by saying we get all 28 frequencies we paid for and they do have various options as to how select and use them in a time domain application in the receiver. The myth about three or four transmitted frequency is just that a myth. Give me a while to study all the patents as it takes a lot of time to go through all of the patents.</span>
HH, Cody