Welcome to the VHF Source readme. This file contains some information that 
should be of value if you are building the Hagtronics VHF Source project.

Be sure to check the FAQ page at www.sonic.net/~shageman for a full and
up to date FAQ page.

Contents: 

	1) Building / turn on notes
	2) Clibration Procedure


1) Building / turn on notes
========================================================================
 Here are some turn on notes I made while assembling my third and last 
 VHF Source. It's not that I don't like building three, but how many 
 does one man really need anyway?
     
 Steve Hageman - 11Oct99
     
     1) Build the power supply first, adjust the 17 volt output. Test the 
     other outputs. BTW - The +5 volt unreg output will be around 12 volts 
     unloaded, this is normal. Don't forget a medium size heat sink (1 inch 
     by 1.5 inches is about right) for U1.
     
     2) Build the NCO board . When done power it up, measure the 40 MHz 
     oscillator, it should be running. Also the 10 MHz PIC and PLL1 clocks 
     should be operating. The 10.7 MHz output should not be doing anything 
     as the HSP45102 NCO needs to be programmed for it to operate.
     
     3) Build the CPU board. Check it's on board +5 and 15 volt regulators. 
     Place the PIC in the board and fire it up. At this point you can tell 
     if the PIC is running if the level DAC output is around 3.4 volts. Upon 
     startup the PIC try's to program everything to a known state. If the 
     level DAC is right (which implies that the PIC is running), then 
     connect the NCO board and restart the PIC. Now the HSP45102 should 
     also be programmed for 10.7 MHz and 10.7 MHz should be present on the 
     NCO board (connector J1). If this is all correct then the NCO board is 
     running and so is the CPU board.
     
     4) Build the PLL boards. Connect them to the CPU and NCO boards and 
     fire up the whole shebang. PLL 1 is programmed to 750 MHz upon 
     powerup. J2 on the PLL 1 board should have 750 MHz @ 9 dBm present.
     
     PLL 0 is programmed for 740 MHz at powerup. So J2 on PLL 0 should have 
     740 MHz @ 9 dBm present. 
     
     Further, if the PLL's are locked, the output of U2 will be around 14 
     volts (i.e. not railed) also the voltage at the lock indicator outputs 
     will be +5 volts. 
     
     If all this is true then the PLL's are working.
     
     5) Build and connect the Mixer Board. Connect the PLL's and the 
     leveling circuit to the CPU board. Upon powerup the CPU will program 
     everything for an overall output of 10 MHz at about 0 dBm. This is 
     because PLL 0 is 740 MHz and PLL 1 is 750 MHz, the difference is 10 
     MHz (i.e. at the output of the mixer). You should be able to trace 
     this 10 MHz signal all the way through the amplifier /filter chain. 
     Further, the leveled output line should be at 0 volts signifying that 
     the output AGC circuit is operating and leveled. If you remove the PLL 
     0 signal from the Mixer board then the leveled signal should be at +5 
     volts signifying that the loop could not be leveled at 0 dBm, this 
     further verifies that the output AGC circuit is running properly.
     
     6) At this point all the internal circuitry of the VHF source is 
     operating. Connect the source to a PC and run the source program. If 
     you have any problems, check that the data LED flickers during program 
     startup. Check that the voltages are getting from the PC back to the 
     PIC (remember that the MAX232 inverts the signals). Also the MAX232 
     should have about +8 to +9 volts on pin 2 and -8 to -9 volts on pin 6.
     
     7) Hopefully all is running at this point, you should now read the 
     section on calibration to finish your VHF source.
     


========================================================================
2) Hagtronics Synthesized VHF Source Calibration Procedure

Version: 15Aug99

Purpose: To define the steps required to preform a calibration
of the sources frequency and amplitude.

Required Equipment:

	For Frequency: An accurate frequency counter. The 
	Calibration will be no more accurate than the counter
	used. The counter needs to be able to measure at 200 MHz.

	For Amplitude: A power meter or quality spectrum
	analyzer that is capable of measuring +17 to -20 dBm at
	10 MHz to better than 0.1 dBm accuracy. A scope is also
	an alternative (although the accuracy of the calibration
	will be lower with a scope).

	You will also require a suitable program or scientific
	calculator that is able to perform linear regression curve
	fitting on a series of data points (linear, straight line curve
	fit is all that is required). If you do not have a suitable program
	check on the web at www.zdnet.com or www.download.com and search for
	'linear regression'. Many freeware or shareware programs are 
	available on the web that are suitable for this simple analysis.


Procedure:

Frequency:
	1) Start the VHF_Source Graphical User Interface (GUI).
	2) From the menus, select Calibration.
	3) From the calibration screen, select "All calibration off".
	Then press OK. The GUI will display a red warning that the 
	calibration is off.
	2) Set the frequency to 200 MHz, set the power to 0 dBm.
	3) Measure the frequency with the counter to the best accuracy
	possible. Then figure out how many percent the source is away
	from 200 MHz. For instance,

		If the counter measured: 199.9900 MHz then the source error is

			Error = ((199.990-200) / 200) * 100 = -0.005%

	4) Select the calibration screen again, set "All calibration on",
	then enter the frequency error (in percent) in the upper box.
	5) Press OK.
	6) The warning message should now be off.
	7) End the program by pressing the X in the upper right hand
	corner of the screen. This saves the value to the VHF_Source.ini
	file.
	8) When you restart the program, the frequency will now be calibrated.


Amplitude:
	Amplitude Linearity Correction Procedure:
	1) Connect a suitable power measuring device to the source.
	2) Start the VHF_Source Graphical User Interface (GUI).
	3) From the menus, select Calibration.
	4) From the calibration screen, select "All calibration off".
	Then press OK. The GUI will display a red warning that the calibration
	is off.
	5) You will notice a number called the 'Level DAC Value' next to the
	amplitude controls. This is the actual DAC code that is loaded in the
	leveling DAC. This value will be used during the calibration procedure
	that follows.
	6) Set the frequency to 10 MHz.
	7) Set the level control so that the measured, actual power is 15 dBm.
	Record the Level DAC Value.
	8) Now lower the level by 5 dBm and likewise record the Level DAC Value
	for each measurement (i.e. measure at +15, +10, +5, 0, -5....-20).
	9) You now have a table of measured power versus DAC values. Feed these 
	values into your linear regression program. The DAC values are the 'Y' 
	entry and the actual power measurement is the 'X' values. The result
	of the analysis is an equation of the form: Y = mX + b
	m should be about 43 and b should be about 2800 or something went wrong
	in the calculations (most likely, the x and y values were switched).
	10) Locate the VHF_Source.ini file on your computer (should be in the 
	'c:\windows' directory), open the file with notepad (or some other text
        editor) and change the following 'keys' to the values you
	just calculated,

		ACL_A = m      ACL_B = b   (m and b from equation above)

	11) Save the VHF_Source.ini file.

	Frequency Correction Procedure:
	1) With the GUI still running, set the actual measured power to 0 dBm at
	10 MHz.
	2) Again make a table of the actual dBm measured versus frequency. The
	table this time will be Frequency, dBm pairs.
	3) Start at 2, 10 and every 10 MHz until 250 MHz (i.e. 26 pairs of values).
	4) Again fit a curve to this data. The Y value is the amplitude delta 
	from 0 dBm and the X is the frequency in MHz.
	5) The values calculated should be about: m = 0.0073, b = 0.09
	10) Locate the VHF_Source.ini file on your computer (should be in the 
	c:\windows directory), open the file with notepad (or some other text
        editor) and change the following 'keys' to the values you just calculated,

		FCL_A = m   and FCL_B = b

	11) Save the ini file, exit Notepad (or the text editor you were using),
	then shutdown the GUI. Restart the GUI and the surce should be calibrated 
	to typically 0.5 dB over the entire frequency / amplitude range.

	Note: 
	If you just need to make a slight offset level adjust, you should 
	modify the ACL_B value. Reducing this value by 44 counts adjusts the output
	down -1 dB (So 4.4 counts equals 0.1 dB). Round the value to the nearest
        whole integer.


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