Unless you have a particularly quirky receiver, leave it at 0. Quoting from the source kit (README-DSPBEW): Baseband Examination Window Typically, the discriminator of an FM communications receiver produces results containing audio spectrum from the "sub-audible" range (typically < 100 Hz) to well above frequencies able to be produced by modulating audio. These higher frequencies can be utilized to determine signal quality, since they can only contain noise (or no noise, if a sufficiently strong signal is present). For receivers (such as the Motorola Quantar, etc) that do not provide sufficient spectral content at these "noise" frequencies (for various reasons), The "DSP/BEW (Digital Signal Processor / Baseband Examination Window)" feature of the RTCM firmware may be utilized. These receivers are perfectly capable of providing valid "noise" signal with no modulation on the input of the receiver, but with strong modulation (high frequency audio and high deviation), it severely interferes with proper analysis of signal strength. This feature provides a means by which a "Window" of baseband (normal audio range) signal is examined by a DSP and a determination of whether or not sufficient audio is present to cause interference of proper signal strength is made. During the VERY brief periods of time when it is determined that sufficient audio is present to cause interference, the signal strength value is "held" (the last valid value previous to the time of interference) until such time that the interfering audio is no longer present. The DSP/BEW feature is selectable, and should not be used for a receiver that does not need it.
From: bill.hurlock@cpcomms.com To: app_rpt-users@ohnosec.org Date: Tue, 19 Mar 2013 18:21:50 +0000 Subject: [App_rpt-users] RTCM Parameter question
I can't seem to find any reference to what item 17 does in the RTCM setup menu. It says DSP/BEW and appears to have 2 choices 0 or 1.
Bill Hurlock CPCommunications 856-234-1661 Home Office 856-264-1010 Cell 914-345-9292 Ext.429 www.cpcomms.com WA2TQI
Providing Solutions for Audio and Video Communications
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