#Test tone generator software full#
#Test tone generator software software#

Adjustments can be made to accept weaker signals and those that are further from the initial sample rate. Ampl., or one that is not within the Max Deviation From Initial Sample Rate. Possible problems include a signal that is below Min. If there is a problem this box will show red. If the signal is usable the Status box will display a yellow 'Collecting data for Block #1, #2 or #3' message while data is being gathered. Once the station is selected, check the Enabled box and press Apply. You may wish to select another station depending on your geographic location (see Notes below). In the Frequency Error Compensation/Calibration window I chose NAA at 24 kHz as it is quite strong here in the northeast. In the Test Tone Generators window adjust the settings as shown (or use your preferred settings) and press Turn On. Close the 'Spectrum Lab Components' window to make room on the display.

Open the Spectrum Lab Components window and press the 'SR Cal' and 'Signal Generator' buttons and to activate those functions and click in the grey switch box to make the connection as shown. With any luck you'll see a number of VLF signals in the waterfall as in the picture below. For a 48 kHz sampling rate sound card these enties should be 48000. At this point check Options > Audio Settings to see that Sound Card Sample Rate is at 96000 and that the entry in the Sample Rate Calibration Table (Hz) for Input Calib is 96000.

Select the appropriate input under Options > Audio Settings. Start Spectrum Lab and load the r file from File > Load Settings From. This rД«efore starting Spectrum Lab connect the VLF antenna to the mic or line audio input jack. usr files that have been pre-configured for specific applications.

#Test tone generator software software#

One nice feature of the software is the ability to load. The following description is for those that have some experience with the program. Spectrum Laboratory is serious software with incredble capabilities so it is well worth learning. In fact, in WOLF frequency measurement mode there is no measurable difference between the computer generated 800 Hz tone and that from a GPS disciplined HP signal generator! This would indicate the frequency accuracy is within a mHz.ДЇirst time users of Spectrum Laboratory may find it a daunting experience as moving up the learning curve can be a slow process. Once the sampling rate correction has been applied, the frequency from the generator is very accurate. The second part of the setup is the Spectrum Laboratory Test Tone Generator. A 'suitable' antenna could be an active e probe or loop antenna with good VLF response or, depending on your distance from a VLF transmitter, something as simple as a length of wire outside on the ground. A 'suitable' VLF antenna is connected directly to the soundcard mic or line input.

To accomplish this, the computer sound card is used as a VLF receiver. This information is used to correct the sound card sampling rate on a continuous basis. Basically, by receiving a VLF signal with MSK modulation, and after a significant amount of computer processing, it's possible to determine the frequency and therefore the sampling rate with great accuracy. A complete description of the Frequency Error Compensation/Calibration feature can be found here. The concept involves using two features that are built into the Spectrum Laboratory software - the Frequency Error Compensation/Calibration routine and the Test Tone Generator. All that is needed is a spare computer (with a 96 kHz sampling rate soundcard - 48 kHz may also work) and Spectrum Laboratory software. Described here is a relatively simple method to generate extremely accurate audio tones, rivalling those from a GPS referenced signal generator. In the past, schemes have been devised using Loran to provide a cal signal but this option no longer exists. For those lacking test equipment the job is considerably more difficult. For stations that have GPS referenced signal generators the cal procedure is simple.

#Test tone generator software full#

While some weak signal programs perform adequately with less than optimum calibration, others such as WOLF require very accurate calibration to get the full benefit of the program's weak signal performance. One of the more difficult tasks to perform without the aid of a highly accurate signal generator is sound card sampling rate calibration. Using a 'Spare' Computer & Spectrum Laboratory

Ultra Accurate Audio Frequency Generator Using a 'Spare' Computer & Spectrum Laboratory For Sound Card Calibration