Phoenix Geophysics Ltd. TXU-30 Current Source Available Waveforms
DomainRatio
ON:OFFTime

1:1

Duty Cycle

Waveform

50%
bipolar

1:1:1:1
Time

1:2

33.33%
bipolar1 : 2 :1 : 2
Time

1:325%
bipolar

1:3 :1: 3
Frequency—

100%
bipolar

1:1
Frequency( f + 9f )10:8

55.55% bipolar
1:1

1
Time

1:1:

150%
unipolar positive

1:1:1:1
Time

1:2

33.33%
unipolar positive

1 : 2 :1 : 2
Time

1:325%
unipolar positive

1:3 :1: 3
Time

1:150%
unipolar negative

1:1:1:1
Time

1:233.33%
unipolar negative

1 : 2 :1 : 2
Time

1:325%
unipolar negative

1:3 :1: 3= Aligned with 2000/01/01 00:00:00 UTC.

PHOENIX Geophysics Limited
3781 Victoria Park Avenue, Unit 3
Toronto, ON, Canada M1W 3K5
www.phoenix-geophysics.com: +1 (416) 491-7340

: +1 (416) 491-7378: mail@phoenix-geophysics.com

Subject to change without notice. © 2006 Phoenix Geophysics Ltd.

TXU-30 Geophysical Current Source Frequencies

Manual and automatic
frequency selection
The TXU-30 Current Source output isadjustable for both frequency domainand time domain methods. In time
domain, output can be bipolar orunipolar.
The TXU-30 has a built-in table offrequencies that can be selectedmanually using the controller. However,Phoenix current source controllers andSystem 2000.net receivers are also
capable of automatically transmitting
and receiving specific signal frequencies
according to a GPS-synchronizedschedule. (The built-in frequency table
represents only a small subset of thefrequencies that are possible using aschedule.)
Schedule files can be created on a PC
and the files transferred to theinstruments, or a schedule can becreated by the instruments in real time,
calculated from a small set ofparameters. Schedule files created for
the TXU-30 specify a waveform, a seriesof frequencies, a duration for eachfrequency, and the current for eachfrequency.
Schedules created by the TXU-30 in realtime are determined by a few
parameters saved in a file. Theseschedules specify a waveform, a seriesof frequencies, a minimum duration foreach frequency, a minimum number ofcycles for low frequencies, and therequested current. Optionally, an
automatic current roll-off can bespecified to prevent inductive loads fromtriggering a fault at higher frequencies.

Phase
For synchronization with other Phoenix
GPS-equipped instruments, the phase issuch that if the waveform wereextended backward in time, the centreof the positive on time (or the negativeon time in unipolar negative) wouldalign with 2000/01/01 00:00:00 UTC.

Frequency
System 2000.net instruments derivefrequencies from a 921.6kHz basefrequency, and therefore may not beable to produce exactly the requested
frequency. Use at least 6 (preferably 8)
significant digits when specifying afrequency. The instruments will calculate
the closest approximation possible.
The highest frequencies available are
9600Hz for frequency domain modes;
30Hz for time domain modes; and 8Hz
for the special FD9 mode ( f + 9f ) .
For best results in frequency domain
methods, use frequencies from Table 1
that follows. For time domain methods,
use frequencies at or below 30Hz fromthe same table.
Frequencies available for manual
selection from the controller are shownin Tables 2 and 3.

PHOENIX Geophysics Limited3781 Victoria Park Avenue, Unit 3
Toronto, ON, Canada M1W 3K5
www.phoenix-geophysics.com: +1 (416) 491-7340

: +1 (416) 491-7378: mail@phoenix-geophysics.com

October 2006. Subject to change without notice. ©2006 Phoenix Geophysics Limited

Table 1: Recommended frequencies

7680.000 3840.000 1920.000

1706.667
6400.000 3200.000 1600.000
3072.000 1536.000
2844.444 1422.222
5120.000 2560.000 1280.000
9600.000 4800.000 2400.000 1200.000

8533.333 4266.667 2133.333 1066.667

16.00000
15.36000
15.00000
14.81481
14.22222
13.33333
12.80000
12.50000
12.00000
11.85185
11.11111
10.66667
10.00000
9.60000
9.37500
8.888898.53333
8.33333

Frequency (Hz)1024.0000 512.0000 256.0000 128.0000 64.00000
61.44000
960.0000 480.0000 240.0000 120.0000 60.00000
948.1481 474.0741 237.0370 118.5185 59.25926
56.88889
853.3333 426.6667 213.3333 106.6667 53.33333
51.20000
800.0000 400.0000 200.0000 100.0000 50.00000
768.0000 384.0000 192.0000
96.0000 48.00000
47.40741
711.1111 355.5556 177.7778
88.8889 44.44444
341.3333 170.6667
85.3333 42.66667
640.0000 320.0000 160.0000
80.0000 40.00000
614.4000 307.2000 153.6000
76.8000 38.40000
600.0000 300.0000 150.0000
75.0000 37.50000
568.8889 284.4444 142.2222
71.1111 35.55556
34.13333
533.3333 266.6667 133.3333
66.6667 33.33333

Frequency (Hz)8.000000 4.000000 2.000000
7.680000 3.840000 1.920000
7.500000 3.750000 1.875000
7.407407 3.703704 1.851852
7.111111 3.555556 1.777778
6.666667 3.333333 1.666667
6.400000 3.200000 1.600000
6.250000 3.125000 1.562500
6.000000 3.000000 1.500000
5.925926 2.962963 1.481481
5.555556 2.777778 1.388889
5.333333 2.666667 1.333333
5.000000 2.500000 1.250000
4.800000 2.400000 1.200000
4.687500 2.343750 1.171875
4.444444 2.222222 1.111111
4.266667 2.133333 1.066667
4.166667 2.083333 1.041667

32.00000
30.72000
30.00000
29.62963
28.44444
26.66667
25.60000
25.00000
24.00000
23.70370
22.22222
21.33333
20.00000
19.20000
18.75000
17.77778
17.06667
16.66667

Period (s) Frequency Period (s) Frequency Period (s)1.000000 1.000000
0.500000 2.000000
0.250000 4.000000
0.960000 1.041667
0.480000 2.083333
0.937500 1.066667
0.468750 2.133333
0.234375 4.266667
0.925926 1.080000
0.462963 2.160000
0.888889 1.125000
0.444444 2.250000
0.833333 1.200000
0.416667 2.400000
0.208333 4.800001
0.800000 1.250000
0.400000 2.500000
0.200000 5.000000
0.781250 1.280000
0.390625 2.560000
0.750000 1.333333
0.375000 2.666667
0.187500 5.333333
0.740741 1.350000
0.370370 2.700000
0.185185 5.400000
0.694444 1.440000
0.347222 2.880000
0.666667 1.500000
0.333333 3.000000
0.166667 5.999999
0.625000 1.600000
0.312500 3.200000
0.156250 6.400000
0.600000 1.666667
0.300000 3.333333
0.150000 6.666667
0.585938 1.706667
0.555556 1.800000
0.277778 3.600000
0.138889 7.199999
0.533333 1.875000
0.266667 3.750000
0.520833 1.920000
0.260417 3.840000

October 2006. Subject to change without notice. ©2006 Phoenix Geophysics Limited

Table 1: Recommended frequencies (continued)
Frequency Period (s) Frequency Period (s) Frequency Period (s)0.1250000 8.00000
0.0625000 16.00000
0.0312500 32.00000
0.1200000 8.33333
0.0600000 16.66667
0.0300000 33.33333
0.1171875 8.53333

Frequency Period (s)0.01562500 64.0000
0.01500000 66.6667

Frequency Period (s)0.00781250 128.000
0.00750000 133.333

0.1111111 9.00000
0.1041667 9.60000
0.1000000 10.00000

0.0555556 18.00000
0.0520833 19.20000
0.0500000 20.00000

0.0277778 36.00000
0.0260417 38.40000
0.0250000 40.00000

0.01388889 72.0000
0.01302083 76.8000
0.01250000 80.0000

0.00694444 144.000

0.0937500 10.66667
0.0925926 10.80000

0.0468750 21.33333
0.0462963 21.60000

0.0234375 42.66667
0.0231482 43.20000

0.01157407 86.4000

0.00578704 172.800

0.0833333 12.00000
0.0781250 12.80000
0.0750000 13.33333

0.0416667 24.00000
0.0390625 25.60000
0.0375000 26.66667

0.0208333 48.00001

0.01041667 96.0000

0.00520833 192.000

0.0187500 53.33333

0.00937500 106.6667

0.00468750 213.333

0.0694444 14.40000
0.0666667 15.00000

0.0347222 28.80000
0.0333333 30.00000

0.0173611 57.60000
0.0166667 59.99999

0.00868056 115.2000
0.00833333 120.0000

0.00434028 230.400
0.00416667 240.000

0.00625000 160.000

0.00390625 256.000

October 2006. Subject to change without notice. ©2006 Phoenix Geophysics Limited

Table 3: Manually selectable frequencies (Hz),time domain

Table 2: Manually selectable frequencies (Hz),frequency domain
9600.00

7680.00

6400.00

30.0000

25.0000

4800.00

3840.00

3200.00

2844.44

16.0000

10.0000

8.33333

2400.00

1920.00

1600.00

1422.221200.00

8.00000

5.00000

1024.00

960.000

800.000

711.111600.000

4.00000

2.50000

512.000

480.000

400.000

355.555

300.000

2.00000

256.000

213.333

170.667

150.000

1.00000

128.000

106.667

85.3333

75.0000

0.500000

64.0000

53.3333

42.6667

37.5000

0.250000

32.0000

26.6667

21.3333

18.7500

0.125000

0.0666667

16.0000

13.3333

10.6667

9.37500

0.06250000

0.03333333

8.00000

6.666675.33333

4.68750

0.03125000

0.0166667

4.00000

3.33333

2.666672.34375

0.01562500

0.00833333

2.00000

1.666671.33333

1.17188

0.00781250

1.00000

0.833333

0.666667

0.600000

0.500000

0.416667

0.333333

0.300000

0.250000

0.208333

0.166667

0.150000

0.125000

0.1041667

0.0833333

0.0750000

0.0666667

0.0625000

0.0520833

0.0520833

0.0416667

0.0333333

0.0312500

0.0260417

0.0208333

0.0187500

0.0166667

0.0156250

0.0130208

0.0104167

0.0937500

0.00833333

0.00781250

0.00520833

0.00468750

0.00416667

0.00390625

October 2006. Subject to change without notice. ©2006 Phoenix Geophysics Limited