Syntax of Synthesizer Commands 		19 Apr 02

    There are two models of synthesizers used at the HHT.  One model, HP 8671B,
outputs the 6-10 GHz to the harmonic mixer.  (There are three of these.)  The
other model, HP 3336C, outputs 50 MHz (to a doubler) to generate the 100 MHz
Phase Lock Loop reference.  (There are two of these.  We steer this slightly
to keep the desired frequency centered in the channels, since the 8671B has
too coarse a resolution to do this in the first place.)

	The command strings below should be followed by a <CR><LF>.  The two
models have different command syntaxes.  The commands sent by the control
system are: 

HP 3336C:

	FRnnnnnnnn.nnnHZ	nnnnnnnn.nnn is the frequency in Hz.

The HP 3336C will also send back the above string if it is addressed to talk.


HP 8671B:

	PnnnnnnnnZ1		nnnnnnnn is the frequency in KHz, (8-digits 
				with leading zeros)
	K0L0O3			Set the output to +10dBm range with a Vernier
				setting of 3; set the ALC to Internal +10 range

The above is what we usually use, the full syntax of the command is KxLyOz
where x, y, and z are single characters that mean: 

    character	 x	 y	    z
	0	0 dB	3 dB	Int, Normal, Off
	1	-10	2	Int, Normal, On
	2	-20	1	Int, +10, Off
	3	-30	0	Int, +10, On
	4	-40	-1	Xtal, Normal, Off
	5	-50	-2	Xtal, Normal, On
	6	-60	-3	Xtal, +10, Off
	7	-70	-4	Xtal, +10, On
	8	-80	-5
	9	-90	-6
	:	-100	-7
	;	-110	-8
	<		-9	Mtr, Normal, Off
	=		-10	Mtr, Normal, On
	>			Mtr, +10, Off
	?			Mtr, +10, On


This synthesizer will NOT send back anything other than a SRQ status byte.