# HELP: USRP1+WBXv3 "Overflow" **URL:** \ **Category:** GNU Radio\ **Created:** [December 16, 2014, 6:25am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464 "2014-12-16T06:25:01Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [December 16, 2014, 6:25am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/1 "2014-12-16T06:25:01Z")
_Good day,_ _We are beginners using the USRP1 with WBX v.3 50-2200 daughterboard and GNU radio Companion version 3.7.5.1 with UHD\_003.008.000-18-g864f84b5 installed on Ubuntu 14.04 LTS operating system. Our goal in using these is to create an SDR WBFM receiver.We have followed what was done in the video posted by the ettus research ([http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio](http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio) [http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio](http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio)) but have encountered some problems. As we ran the GRC file, both the FFT plot and Scope plot appeared but all we could hear are static sounds together with the script shown below:_ Executing: “/media/thesis/Data/Downloads/Thesis/FM Reciever using GRC/fm\_example.py” linux; GNU C++ version 4.8.2; Boost\_105400; UHD\_003.008.000-18-g864f84b5 Using Volk machine: sse4\_1\_64\_orc – Opening a USRP1 device… – Using FPGA clock rate of 64.000000MHz… ## UHD Warning: The hardware does not support the requested RX sample rate: Target sample rate: 5.000000 MSps Actual sample rate: 5.333333 MSps – Tune Request: 88.100000 MHz – The RF LO does not support the requested frequency: – Requested LO Frequency: 88.100000 MHz – RF LO Result: 88.099634 MHz – Attempted to use the DSP to reach the requested frequency: – Desired DSP Frequency: -0.000366 MHz – DSP Result: -0.000366 MHz – Successfully tuned to 88.100000 MHz INFO: Audio sink arch: alsa OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO > > > Done _As we are doing all the simulations, we did not use any antenna yet. However, we are waiting for the arrival of the antenna LP0410 400 MHz to 1 GHz Log Periodic PCB directional antenna, at 5-6dBi Gain. We have purchased this antenna for it is capable to receive signals from 88.1MHz to 107.9MHz (frequency range of all the FM stations that we are about to receive)._ _-SKA15-_ ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 16, 2014, 6:34am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/2 "2014-12-16T06:34:31Z")
On 12/16/2014 12:24 AM, Thesis 2015 wrote: > ([http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio](http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio)) > – Opening a USRP1 device… > – Attempted to use the DSP to reach the requested frequency: > However, we are waiting for the arrival of the antenna LP0410 400 MHz > Discuss-gnuradio mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) > The example is designed for an N200/N210, for which a 5Msps sample-rate > is legal. On the USRP1, the master-clock is at 64MHz, so you can’t produce 5Msps from that, since that isn’t an integer fraction of the master-clock rate. Re-jig the graph to use 4Msps as the input sample-rate. Pay attention to parts of the graph where it interpolates or re-samples, and make certain that re-sampling will still work with a 4Msps sample-rate. ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 16, 2014, 7:43am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/3 "2014-12-16T07:43:55Z")
An antenna made for 400-1000 MHz is not exactly the right thing to receive 88-108 MHz 🙂 Just use a piece of wire, length about 75cm, this should be enough for first tests. Ralph. From: [discuss-gnuradio-bounces+ralph=removed\_email\_address@domain.invalid](mailto:discuss-gnuradio-bounces+ralph=removed_email_address@domain.invalid) [[mailto:discuss-gnuradio-bounces+ralph=removed\_email\_address@domain.invalid](mailto:discuss-gnuradio-bounces+ralph=removed_email_address@domain.invalid)] On Behalf Of Thesis 2015 Sent: Tuesday, December 16, 2014 6:24 AM To: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Subject: [Discuss-gnuradio] HELP: USRP1+WBXv3 “Overflow” Good day, We are beginners using the USRP1 with WBX v.3 50-2200 daughterboard and GNU radio Companion version 3.7.5.1 with UHD\_003.008.000-18-g864f84b5 installed on Ubuntu 14.04 LTS operating system. Our goal in using these is to create an SDR WBFM receiver. We have followed what was done in the video posted by the ettus research ([http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio](http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio)) but have encountered some problems. As we ran the GRC file, both the FFT plot and Scope plot appeared but all we could hear are static sounds together with the script shown below: Executing: “/media/thesis/Data/Downloads/Thesis/FM Reciever using GRC/fm\_example.py” linux; GNU C++ version 4.8.2; Boost\_105400; UHD\_003.008.000-18-g864f84b5 Using Volk machine: sse4\_1\_64\_orc – Opening a USRP1 device… – Using FPGA clock rate of 64.000000MHz… UHD Warning: ``` The hardware does not support the requested RX sample rate: Target sample rate: 5.000000 MSps Actual sample rate: 5.333333 MSps ``` – Tune Request: 88.100000 MHz – The RF LO does not support the requested frequency: – Requested LO Frequency: 88.100000 MHz – RF LO Result: 88.099634 MHz – Attempted to use the DSP to reach the requested frequency: – Desired DSP Frequency: -0.000366 MHz – DSP Result: -0.000366 MHz – Successfully tuned to 88.100000 MHz – INFO: Audio sink arch: alsa OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO > > > Done As we are doing all the simulations, we did not use any antenna yet. However, we are waiting for the arrival of the antenna LP0410 400 MHz to 1 GHz Log Periodic PCB directional antenna, at 5-6dBi Gain. We have purchased this antenna for it is capable to receive signals from 88.1MHz to 107.9MHz (frequency range of all the FM stations that we are about to receive). -SKA15- ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 17, 2014, 9:44am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/4 "2014-12-17T09:44:28Z")
We’re sorry. We made a mistake with the frequency range that the antenna could receive. It is actually 40MHz - 1.2GHz. -SKA15- ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 17, 2014, 11:07am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/5 "2014-12-17T11:07:29Z")
I’m afraid you did not make a mistake – the LP0410 [1] is specified for usage between 400 and 1200 MHz. Whilst it will still pick up some signal at frequencies below 400MHz, operating it at a quarter of the lower cutoff freq. will lead to very suboptimal results. If you know your frequency range as well as you do, I recommend trying Ralph’s proposed 1/2 wavelength monopole antenna. Greetings, Marcus [1][LP0410 Antenna | Ettus Research, a National Instruments Brand | The leader in Software Defined Radio (SDR)](http://www.ettus.com/product/details/LP0410) ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 17, 2014, 5:20pm UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/6 "2014-12-17T17:20:45Z")
Considering the saturation level of most commercial FM stations, using a simple whip antenna will prove more than adequate. While a wide-range log-periodic antenna might prove useful as you get farther into your research, especially for broadband signals requiring a directional antenna, using simpler tools while learning is usually beneficial. gerry On Wed, Dec 17, 2014 at 4:06 AM, Marcus Müller [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Discuss-gnuradio mailing > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > * * * > > Discuss-gnuradio mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) – Gerry Creager NSSL/CIMMS 405.325.6371 ++++++++++++++++++++++ “Big whorls have little whorls, That feed on their velocity; And little whorls have lesser whorls, And so on to viscosity.” Lewis Fry Richardson (1881-1953) ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 23, 2014, 8:15am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/7 "2014-12-23T08:15:49Z")
Hello SKA15, well, I’m pretty sure there is some way to do this in GRC; but honestly, this sounds like something that would be very little lines of code in python; I recommend going through the guided tutorials [1] in order to understand how to write a python block that will emit the right stream tags at the right time. Greetings, Marcus [1] [http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorials](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials) ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 23, 2014, 4:41am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/8 "2014-12-23T04:41:58Z")
Good Day, We are able to receive FM signals using the USRP1 with WBXv3 50-2200 having a 750cm solid wire that serves as an antenna. We were wondering how to modify the generated GRC python code. We are planning on changing the center frequency automatically with an interval of 200MHz in a specified time. Thank you. -SKA15- On Thu, Dec 18, 2014 at 12:19 AM, Gerry Creager - NOAA Affiliate \< ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 29, 2014, 12:44pm UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/9 "2014-12-29T12:44:06Z")
Hello SKA15, I don’t understand what you refer to, sorry. Anyway, what I can tell is that this is something that most probably gets easier by actually trying, so go ahead and implement it. I think I’ve given you some inspiration in the form of using stream tags with your device block. From your mail address I’d guess that you’re writing a thesis – that would be something that will lead to experience and documentable progress. Greetings, Marcus ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 29, 2014, 4:14am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/10 "2014-12-29T04:14:13Z")
Good day. Would it be fine if we placed a while or for loop statement under the variables section so that it would increment by 200kHz and would change to different frequencies within the FM spectrum. If you have any other ideas that could help us, it would be greatly appreciated. -SKA15- ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [December 30, 2014, 6:19pm UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/11 "2014-12-30T18:19:07Z")
On Sun, Dec 28, 2014 at 10:13 PM, Thesis 2015 [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Good day. > Would it be fine if we placed a while or for loop statement under the > variables section so that it would increment by 200kHz and would change to > different frequencies within the FM spectrum. > If you have any other ideas that could help us, it would be greatly > appreciated. > > -SKA15- As Marcus said, feel free to play with these things to figure it out. But one hint you’ll probably need is that any changes to the flowgraph need to happen after the top\_block has already started. So look for the tb.run() or tb.start(). If using tb.run() this is a blocking call that you’ll need to change: tb.start() tb.stop() tb.wait() Something like that. Tom ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [February 5, 2015, 8:43am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/12 "2015-02-05T08:43:19Z")
Hi Thesis, first of all: be sure to actually copy and paste the code you’re using; what you’ve pasted can’t run, since python is case sensitive and start() and wait() are written in lower letters. I don’t understand what you mean with “close the scope”; can you elaborate? Greetings, Marcus ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [February 5, 2015, 5:14am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/13 "2015-02-05T05:14:43Z")
Hello everyone! We have been able to modify the python file to allow the receiver to jump from one frequency to another. We have modified it to be able to receive signals from local FM stations and jump from one frequency to another using the python file attached. (Note:we modified it at the end part using: tb1 = fm\_example() tb1.Start(True) tb1.Wait() freq = freq+200e3 We have also tried to increment it by 200kHZ for all frequencies using just the same code.We tried it up to tb70 and there is a certain point(after tb33, i believe) where it says the following error.(please see attached image) We would like to ask the following questions: 1.From what I understand, tb.Wait is used for waiting for the flowgraph to finish. WIth the code we used, we close the scope then it runs again with an incremented frequency. Do you have any suggestions as to what code we can use to automatically close the scope so it jumps to another frequency after a certain amount of seconds(lets say 10 seconds)? 2.What causes the error in the second similar code(pls see attached image)? Thank you very much and have a good day. ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [February 5, 2015, 11:57am UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/14 "2015-02-05T11:57:11Z")
Hi Thesis, first of all: be sure to actually copy and paste the code you’re using; what you’ve pasted can’t run, since python is case sensitive and start() and wait() are written in lower letters. I don’t understand what you mean with “close the scope”; can you elaborate? Greetings, Marcus ---
**Author:** ![Thesis\_2015](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/977dab/32.png) [@Thesis\_2015](https://www.ruby-forum.com/u/Thesis_2015)\ **Post date:** [February 7, 2015, 1:37pm UTC](https://www.ruby-forum.com/t/help-usrp1-wbxv3-overflow/233464/15 "2015-02-07T13:37:22Z")
Hello.Sorry about that.Here is the generated code with a few of our modifications at the end. * * * #!/usr/bin/env python ################################################## # Gnuradio Python Flow Graph # Title: Fm Example # Generated: Tue Jan 6 10:37:52 2015 ################################################## from gnuradio import analog from gnuradio import audio from gnuradio import eng\_notation from gnuradio import filter from gnuradio import gr from gnuradio import uhd from gnuradio import wxgui from gnuradio.eng\_option import eng\_option from gnuradio.fft import window from gnuradio.filter import firdes from gnuradio.wxgui import fftsink2 from gnuradio.wxgui import forms from grc\_gnuradio import wxgui as grc\_wxgui from optparse import OptionParser import time import wx class fm\_example(grc\_wxgui.top\_block\_gui): ``` def __init__ (self): grc_wxgui.top_block_gui. __init__ (self, title="Fm Example") _icon_path = ``` “/usr/share/icons/hicolor/32x32/apps/gnuradio-grc.png” self.SetIcon(wx.Icon(\_icon\_path, wx.BITMAP\_TYPE\_ANY)) ``` ################################################## # Variables ################################################## self.samp_rate = samp_rate = 4e6 #self.freq = freq = 88.1e6 self.freq = freq ################################################## # Blocks ################################################## self.notebook_0 = self.notebook_0 = wx.Notebook(self.GetWin(), ``` style=wx.NB\_LEFT) self.notebook\_0.AddPage(grc\_wxgui.Panel(self.notebook\_0), “RF Spectrum”) self.notebook\_0.AddPage(grc\_wxgui.Panel(self.notebook\_0), “Demod Spectrum”) self.Add(self.notebook\_0) self.\_freq\_text\_box = forms.text\_box( parent=self.GetWin(), value=self.freq, callback=self.set\_freq, label=‘freq’, converter=forms.float\_converter(), ) self.Add(self.\_freq\_text\_box) self.wxgui\_fftsink2\_1 = fftsink2.fft\_sink\_f( self.notebook\_0.GetPage(1).GetWin(), baseband\_freq=0, y\_per\_div=10, y\_divs=10, ref\_level=0, ref\_scale=2.0, sample\_rate=600e3, fft\_size=1024, fft\_rate=15, average=False, avg\_alpha=None, title=“FFT Plot”, peak\_hold=False, win=window.rectangular, ) self.notebook\_0.GetPage(1).Add(self.wxgui\_fftsink2\_1.win) self.wxgui\_fftsink2\_0 = fftsink2.fft\_sink\_c( self.notebook\_0.GetPage(0).GetWin(), baseband\_freq=freq, y\_per\_div=10, y\_divs=10, ref\_level=0, ref\_scale=2.0, sample\_rate=samp\_rate, fft\_size=1024, fft\_rate=15, average=False, avg\_alpha=None, title=“FFT Plot”, peak\_hold=False, ) self.notebook\_0.GetPage(0).Add(self.wxgui\_fftsink2\_0.win) self.uhd\_usrp\_source\_0 = uhd.usrp\_source( “,”.join((“serial=2R2CU0U1”, “”)), uhd.stream\_args( cpu\_format=“fc32”, channels=range(1), ), ) self.uhd\_usrp\_source\_0.set\_subdev\_spec(“A:0”, 0) self.uhd\_usrp\_source\_0.set\_samp\_rate(samp\_rate) self.uhd\_usrp\_source\_0.set\_center\_freq(freq, 0) self.uhd\_usrp\_source\_0.set\_gain(15, 0) self.uhd\_usrp\_source\_0.set\_antenna(“RX2”, 0) self.rational\_resampler\_xxx\_0 = filter.rational\_resampler\_fff( interpolation=240, decimation=48, taps=None, fractional\_bw=None, ) self.low\_pass\_filter\_0 = filter.fir\_filter\_ccf(20, firdes.low\_pass( 1, samp\_rate, 100e3, 10e3, firdes.WIN\_HANN, 6.76)) self.audio\_sink\_0 = audio.sink(48000, “”, False) self.analog\_wfm\_rcv\_0 = analog.wfm\_rcv( quad\_rate=600e3, audio\_decimation=20, ) ``` ################################################## # Connections ################################################## self.connect((self.uhd_usrp_source_0, 0), ``` (self.wxgui\_fftsink2\_0, 0)) self.connect((self.uhd\_usrp\_source\_0, 0), (self.low\_pass\_filter\_0, 0)) self.connect((self.analog\_wfm\_rcv\_0, 0), (self.wxgui\_fftsink2\_1, 0)) self.connect((self.low\_pass\_filter\_0, 0), (self.analog\_wfm\_rcv\_0, 0)) self.connect((self.rational\_resampler\_xxx\_0, 0), (self.audio\_sink\_0, 0)) self.connect((self.analog\_wfm\_rcv\_0, 0), (self.rational\_resampler\_xxx\_0, 0)) ``` def get_samp_rate(self): return self.samp_rate def set_samp_rate(self, samp_rate): self.samp_rate = samp_rate self.wxgui_fftsink2_0.set_sample_rate(self.samp_rate) self.uhd_usrp_source_0.set_samp_rate(self.samp_rate) self.low_pass_filter_0.set_taps(firdes.low_pass(1, ``` self.samp\_rate, 100e3, 10e3, firdes.WIN\_HANN, 6.76)) ``` def get_freq(self): return self.freq def set_freq(self, freq): self.freq = freq self.wxgui_fftsink2_0.set_baseband_freq(self.freq) self.uhd_usrp_source_0.set_center_freq(self.freq, 0) self._freq_text_box.set_value(self.freq) ``` if **name** == ‘ **main** ’: import ctypes import sys if sys.platform.startswith(‘linux’): try: x11 = ctypes.cdll.LoadLibrary(‘libX11.so’) x11.XInitThreads() except: print “Warning: failed to XInitThreads()” parser = OptionParser(option\_class=eng\_option, usage=“%prog: [options]”) (options, args) = parser.parse\_args() freq = 88.1e6 ``` tb1 = fm_example() tb1.Start(True) tb1.Wait() freq = freq+200e3 tb2 = fm_example() tb2.Start(True) tb2.Wait() freq = freq+200e3 tb3 = fm_example() tb3.Start(True) tb3.Wait() freq = freq+200e3 tb4 = fm_example() tb4.Start(True) tb4.Wait() freq = freq+200e3 tb5 = fm_example() tb5.Start(True) tb5.Wait() freq = freq+200e3 ``` * * * Actually,we didn’t type Start and Wait in lowercase letters since when we generated the code, the first letters were already capitalized. Also, our code was supposed to be up to tb50(I didn’t paste it all since they were just the same lines of code). But when tb33 runs, an error occurs (please see attached image ) Is there a limit to the number of "tb"s ? We would also like to apologize for our mistake.What we meant by “closing the scope” was closing the output display, after running our modified code so that the next “tb” could run. Do you guys have any suggestions as to how to close the display automatically(for a few seconds,if possible) so that the next “tb” with an incremented freq could run? Thank you very much for your time & help and have a good day. -SKA15- On Thu, Feb 5, 2015 at 6:55 PM, Marcus Müller [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)