GRE/RS/Whistler based DSP ADC/DAC Adjustments
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Revision as of 09:23, 21 August 2017 by Ka3jjz
GRE\RS\Whistler OOS based DSP ADC\DAC Adjustments
The GRE\RS\Whistler Object Oriented Scanners allow users to change the DSP settings, changing the speed of how the incoming signals are dealt with. Then there are the additional 2 settings of ADC & DAC that user's can change. All 3 setting are part-in-partial to how & what is received and decoded. Through deductive reasoning, it stands to reason that an engineer gave "the User" the abilities to change these settings. Most likely, since only a "standard setting" for each, would not be a panacea for all listeners, of every mode and system type. Now, if we all had enough of the same scanners to monitor everything, we could quickly dial-in, what each system type and condition type the settings should be set to, until then, lets go off of multiple users past experiences. This is most generally when we are talking about digital reception & decode, since it's a beast all on it's own, analog audio suffers little with the ADC and DAC both set to their highest settings.
Now the speed at which the DSP handles all transmissions coming in is directly corollary to how it's going to be reproduced by the speaker. There's a finite curve at which any one system type can decode & reproduce intelligible voice, and what works best for one "system type" might not be close to a good setting for another system type, but a balance could possibly be found.
Which Scanners Have The Ability to Change These Settings?
With the exception of the PSR-700 and Pro-107, these scanners should be able to perform these adjustments;
- Released around the time the PSR-800 was, but lacking additional/advanced features SEE #5.
- Project 25(P25) Phase I and II decoding.
- Capable of DMR decoding, with a free Upgrade to the latest Firmware via Whistler's EZ-Scan software.
- Capable of NXDN decoding, with a free Upgrade to the latest Firmware via Whistler's EZ-Scan software
- Ability to be Upgraded for DMR (and add P25 Phase II to Pro-18) decode with a Paid Upgrade with User paid shipment to Whistler, returned by them. Once, returned, continued forward support is possible via Whistler Repair and EZ-Scan Software, with all the newer additions and features of a WS1080.
- Variant with Keypad
- Trunking w Analog Voice Only
- ALL THE SAME after UPGRADE except silk screening
- Never released publicly, subsequently became WS1095
Latest Whistler settings per EZ-Scan 2.18-2.24, definitively applicable to all GRE PSR-800 based Scanners
|Setting||Range Values||Value DEFAULT|
|ADC||+2 to -2||-2|
|DAC||+2 to -10||-4|
|DSP||1 to 255||64|
All 3 settings go hand-in-hand, the received signals starting point after the initial-filtering is then put into the ADC to be converted to a Digital signal that the DSP can handle, or the initial-filtered digital signal pushed to the DSP to be decoded, then either to the display or onto the speaker to be heard. The higher the noise floor - the lower we want the ADC and/or DAC to be pumping signal into the DSP, too high and we can over saturate the DSP (without the signal being very dynamic like when you turn-up the volume all the way on any speakers) where distortion and decode errors begin; too low a setting, and there's barely any signal to amplify, let alone decode.
ADC & DAC adjusting
- For inside a home without any external antenna set-up settings could be closer to 0
- -1 and -2 or -2 and -3
- For set-ups with external antennas, even on window mounts, the lows ends is where we want things to be, closer to middle negatives
- -2 and -6
- -1 and -5
- For mobile set-ups it can varym but generally the lows ends is where we want things to be, closer to middle negatives and lower,
- especially for handhelds when mobile like -2 and -5
- Mobile w/ external mounted antenna -2 and -6
- For downtown Offices in a high rise it also varies, because of the glass type used in windows, building construction and signal orientation to scanner, might be the only time a DAC -10 setting and a stubby antenna is used or just simply attenuation
- A happy medium is the default just as Whistler suggest -2 and -4
|Setting||Way Too MUCH||Too much||A lot||The right amount||Too little||Way Too LITTLE||NO Signal|
|ADC||-2||-2||-2||-2 or -1||-1 or 0||0 or +1||+2|
|DAC||-10 to -6||-6 to -5||-4||-4 or -3||-2 or -1||0 or +1||+2|
DSP lowering from the Default of 64 can help make digital voice clearer to some listeners. Also, it can be used to help mitigate timing offset by nearby scanners that typically produce an echo with the same channel being monitored by both (especially when they are different makes and one is SD card based, try 44 w a x36hp close by, or for older models nearby try 96). When you go to change DSP a recommended level of 8 in either direction is easier to remember as long as you already know your 8 Times-table. ie 64 to 72, 80, 88 or the other direction 64 to 56, 48, 40. Even by trying something as fast as 128 you should be able to audibly discern the sped-up audio processing, or 24 to slow it down.
|Setting||way too slow||Too slow||slow||Right speed||fast||Too fast||Way too fast|
Added adjustments do/may include the Squelch and/or Data Decode Threshold.
- Squelch can usually be adjusted slightly more "open" (Counter-clockwise) for each ADC/DAC level you go down (in negatives) or "closed" as (Clockwise) as ADC/DAC go closer to 0 or positives.
For more info:
- Data Decode Threshold
- Object Oriented Scanners Overload Issues applies to GRE PSR800 based Scanners as well
Note: While the "how to" details differ, this can also be done with Uniden scanners for an improvement in "decoding signals" for a given area (county, city, etc) See HERE
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