Tone Pips

This is a sample menu of the Tone Pip stimulus. A series of tone pips will be generated, starting at the low frequency and ending at the high frequency. The third parameter in the menu, frequency scale, determines whether the steps between successive frequencies will be linear or logarithmic. The size of the steps is determined by the number of frequencies parameter (linear case) or the steps per octave parameter (log case). In this example, there will be 20 tone pips presented at linear intervals between 100 Hz and 8000 Hz. The stimulus duration of each tone pip will be 200 msec and there will be a 300 msec repetition time between the start of successive tones.

			    Low Freq =  100 Hz            Maxspl 1 = 113 dB *
			   High Freq = 8000 Hz            Maxspl 2 = 126 dB *
   Frequency Scale (linear=0, log=1) :    0             DAC bits 1 = 14
    Phone (0=none, 1=1, 2=2, 3=both) :    3             DAC bits 2 = 14
			       SPL 1 =   90 dB             atten 1 = 23 dB
			       SPL 2 =   90 dB             atten 2 = 36 dB
Display (0=none, 1=all, 2=no raster) =    1
		   Stimulus Duration =  200.00 msec
		     Repetition Time =  300.00 msec
      Number of Frequencies (linear) =   20
	      Steps per Octave (log) =    4
	 Freq Diff (phone2 - phone1) =    2.00 Hz
		     Delay of Master =    0 usec
		    Master DSS (1,2) =    1
		      SPL Clip Value =   10 dB
       Speaker # for DSS 1 (0 to 15) :    3 (certain computers only)
       Speaker # for DSS 2 (0 to 15) :   11 (certain computers only)
			     UETCHAN =    0
			    UETCHAN2 =   -1

				    p=^P=Pause, e=^Z=Exit, r=Retrieve, s=Store 
g=^G=Go, w=Dset(newname), u=Dset(inc unit#), x=Dset(inc seq#), d=t=Screen Dump

The Tone Pips routine is binaural. The phone parameter determines which of the two phones is to generate the stimulus.

		0 = neither phone 
		1 = phone 1			(DSS 1)
		2 = phone 2			(DSS 2)
		3 = both phone 1 and phone 2	(DSS 1 and 2)

The freq diff parameter allows for a difference in frequency between phone 1 and phone 2. Here, the tones from phone 2 will be at 2 Hz higher than those from phone 1.

The sound pressure level is specified separately for each phone, with the parameters SPL 1 and SPL 2. Since the phone(s) used in any given experiment will, in general, maintain different sound pressure levels at different frequencies, there is a feature built into the DSS to correct for these different levels. As a result of the SPL correction, the corrected waveform will lose some of its resolution -- 1 bit of resolution for every 6 dB of correction that is done. The parameter SPL clip value is used by the system as a limit of the amount of SPL correction to be made at any frequency. For more information about this important concept, please see the detailed description of SPL correction, which also discusses related parameters and shows a sample graph of an SPL calibration curve.

The delay of master parameter allows for the stimulus of one of the DSS's to be presented at a slight delay after the stimulus of the other DSS. One must first specify the parameter master DSS, as either 1 or 2. Then, depending on which DSS is chosen as the master, the delay will be placed on that DSS. Note that negative delays are allowed.

The parameters speaker # for DSS 1 and speaker # for DSS 2 are used only in certain experimental setups. Here, the stimulus from each DSS is played out through one of several speakers, rather than through a phone. The program allows for 16 speakers, numbered from 0 to 15, and any of these can be selected for either DSS. Currently, the only computer on which this system of speakers is functioning is ECHO. On all other computers, the speaker parameters will be ignored.

An additional feature of the Tone Pips routine is that the user can now specify 2 different input channels for the collection of spikes through the UET (Unit Event Timer). The UET does have 16 input channels, numbered 0 through 15. Channel numbers 2, 3, and 6 are reserved for internal signals, but the user could connect data inputs to any of the other 13 channels. The user must specify the numbers of the 2 channels to be used. The menu parameters UETCHAN and UETCHAN2 are used for this.

If only one UET input channel is being used, then the user should set either UETCHAN or UETCHAN2 to the value of that channel number, and set the other channel parameter to -1. In any case, a channel number of -1 means no input channel and therefore no data to be displayed.

The output Display of the Tone Pips routine has two parts. There is a plot of the accumulation of spikes generated after every series of tones, plus a dot raster display of the spike times during each repetition interval. The display parameter has 3 possible values: 0 = no display, 1 = display both the spike curve and the dot raster, and 2 = display the spike curve but no dot raster.

Note that if both UETCHAN and UETCHAN2 are set to channel numbers other than -1, then 2 spike curves and 2 dot rasters must be included in the output display. The output corresponding to UETCHAN is plotted as solid vectors, while that corresponding to UETCHAN2 is dashed vectors. In the case of a color display, the dashed vectors should show up in a different color. Note that the program runs considerably faster without any data display.

The arrow keys are used to move around in the menu. There are also several single-character commands available to the user at all times, while in the Tone Pips menu. They are listed here, and described in more detail below.

	g, G, or ^G	Start or restart stimulus
	p, P, or ^P	Stop stimulus, stay in Tone Pips menu
	e, E, or ^Z	Stop stimulus, return to SER main menu
	d or D		Dump next spike display to printer
	t or T		Dump next spike display to printer
	s or S		Store current menu params to special block
	r or R		Retrieve menu params stored by 's'
	w or W		Save current data, specify data set name
	u or U		Save current data, increment unit #
	x or X		Save current data, increment sequence #

After setting the parameters to the desired values, the series of Tone Pips is started by typing CTRL-G. At the end of each series of pips, the display (if specified) will be updated and the tones will be generated again. This continues until the user stops the stimulus. As with the FM Sweep routine, 'e' is used to exit, and 'p' stops the stimulus. Any individual parameter can be changed at any time -- type the new value, then hit 'Return' or one of the arrow keys to move the cursor. Then, stimulus will stop and restart with the new parameter values. Note that, as with the FM Sweep, it is can be faster to change a number of parameters by first typing 'p' to stop the stimulus, then modifying the parameters, then hitting 'g' to restart.

With the Tone Pips stimulus there is the special feature of a private storage block for the menu parameters. To store the current set of menu parameters into this storage block, type 's' or 'S'. Then, continue to run the stimulus, changing any parameter to a new value. To retrieve the set of parameters stored by the S command, type 'r' or 'R'.

There is now a hard copy feature, specified with the 'D' or 'T' option. Simply type D or T and the program will send to the printer a copy of the spike curve and dot raster at the end of the current series of tone pips. (The display is only updated at the end of each series of pips, and so both the 'd' and 't' options have been designed to do the same thing, that is, to send a hard copy dump of the next update of the display.) Note that if the Display parameter is set to 2, then there will be no dot raster data in the hard copy. If it is set to 0, the hard copy command will be ignored.

Invalid parameter settings sometimes cause the stimulus to stop. The user must change the appropriate parameter(s), then type 'g' or CTRL-G to restart the stimulus.

To store the response data from the current series of tone pips, the user can type 'w', 'u', or 'x'. Each of these commands stores the data for the entire series of tones. The only difference between the 3 commands is how the name for the new data set is chosen. Each command displays the name of the most recently stored data set. The 'w' command prompts the user to type in a new name for the data set to be stored. The 'u' or the 'x' command will try to automatically create a new data set ID name. They look at the previous name, which is understood to have the format 'unit#-sequence#', preceded by an optional string of characters. For example, a valid name would be abc100-12, where the unit number is 100 and the sequence number is 12. The 'u' command will increment the unit number, and the 'x' command will increment the sequence number. If the previous data set name is not in this format, then each of the commands will prompt the user to type in a new data set id name.

The data for a series of tone pips are stored with the data set type name SRPP, which will distinguish it from data collected during one of the other stimulus options. The schema name for each data set is sch016.

See also the general description of the SER program.
See also the descriptions of the other SER stimulus options:
FM Sweep, Clicks, Noise, Dual Tones