Lines Matching +full:codec +full:- +full:driver
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
4 <meta http-equiv="content-type" content="text/html;charset=iso-8859-1">
13 <!-- #BeginDate format:En2m -->17-Jul-2014 02:17<!-- #EndDate -->
19 Driver ID: <tt>CHU</tt><br>
20 Modem Port: <tt>/dev/chu<i>u</i></tt>; 300 baud, 8-bits, no parity<br>
21 Autotune Port: <tt>/dev/icom</tt>; 1200/9600 baud, 8-bits, no parity<br>
24 <p>This driver synchronizes the computer time using shortwave radio transmissions
25 …from Canadian time/frequency station <a href="http://inms-ienm.nrc-cnrc.gc.ca/time_services/shortw…
31 …driver can be compiled to use either an audio codec or soundcard, or a Bell 103-compatible, 300-b/…
32 …driver is accurate within 1 ms relative to the broadcast time when tracking a station. However, va…
33 …-GHz P4 running FreeBSD 6.1 is generally within 0.2 ms short-term with 0.4 ms jitter. The long-ter…
34 <p>The driver performs a number of error checks to protect against overdriven or underdriven input …
35 …driver incorporates several features in common with other audio drivers such as described in the <…
37 <p>The driver processes 8-kHz μ-law companded codec samples using maximum-likelihood techniques …
38 …-ienm.nrc-cnrc.gc.ca/time_services/chu_e.html">CHU website</a>. A timecode is assembled when all b…
40 …-likelihood UART, burst assembler and majority decoder. The DSP modem demodulates Bell 103 modem a…
41 …-stage shift registers, one for each of eight phases of the 300-b/s bit clock. At each phase a new…
42 …-robin order as the phases of each bit arrive. At the end of each bit all eight phases are searche…
43 <p>The burst assembler processes characters either from the maximum-likelihood UART or directly fro…
44 …-character blocks, each block representing ten 4-bit BCD digits. The format B blocks sent in secon…
45 …B burst the second block is bit-inverted relative to the first, so a perfect burst of five 8-bit c…
47 …-bit code combination that might be decoded at that position. In order to use the character timest…
49 … is the distance for that position and the corresponding code is the maximum-likelihood digit. If …
50 <p>The result of the majority decoder is a nine-digit timecode representing the maximum-likelihood …
51 …face can handle is 60. These are processed using a median filter and trimmed-mean average, so the …
53 …driver includes provisions to automatically tune the radio in response to changing radio propagati…
54 …driver will attempt to open the device <tt>/dev/icom</tt> and, if successful will tune the radio t…
55 …driver cycles over the three frequencies in turn, one minute for each station. When bursts are rec…
57 …-d</tt> on the <tt>ntpd</tt> command line) is enabled, the program produces detailed status messag…
58 <p>With debugging enabled the driver produces messages in the following formats: A single message b…
60 …-11) and <tt>b</tt> the burst distance (0-40). Good bursts will have spans of a 800 or more and th…
61 …-V interface for ICOM radios is active, a debug level greater than 1 will produce a trace of the C…
78 agc audio gain (0-255)
83 …d are in fixed-length format. The <tt>agc</tt> and <tt>lset</tt> fields, as well as the following …
88 …<dd>The quality character is a four-bit hexadecimal code showing which alarms have been raised dur…
111 …<dd>The audio gain shows the current codec gain setting in the range 0 to 255. Ordinarily, the rec…
114 code, if the CI-V interface is active, or <tt>CHU</tt> if not. The radio
127 <dd>Not used by this driver.</dd>
129 <dd>Specifies the driver stratum, in decimal from 0 to 15, with default 0.</dd>
131 …<dd>Specifies the driver reference identifier, an ASCII string from one to four characters, with d…
133 <dd>Not used by this driver.</dd>
135 …<dd>When the audio driver is compiled, this flag selects the audio input port, where 0 is the mike…
137 …udio driver is compiled, this flag enables audio monitoring of the input signal. For this purpose,…