Agilent Technologies 2948, 2712A manual Channel a

Service Model 8904A

CHANNEL A I

PHASE

6‘L FREOUENCY

Figure 8-1.Conceptual Block Diagram of a Standard Instrument

The standard instrument has only one channel-Channel A. Channel A can output one of the six available waveforms. Four of the waveforms (sine, sawtooth, triangle, and square) are periodic and thus have a frequency and phase which can be controlled. The level of all waveforms can be controlled. (Level is controlled in both the DWSIC and the analog output circuits.)

The DWSIC

The DWSIC, in response to front-panel or HP-IB inputs directed to the instrument’s internal computer, generates the basic waveforms (in their digital form) for each channel, modulates and combines them (still in digital form) as requested, and delivers them to the appropriate digital-to-analog converter.

Figure 8-2shows a one-channel portion of the DWSIC. The diagram is highly simplified but detailed enough to illustrate general concepts such as

0generation of a basic sine wave

0setting and modulating its phase

0setting and modulating its frequency

0setting and modulating its amplitude

AM DATA	2						I
	FREOUENCY			I	PHASE		WAVEFORM
	ADDER	PHASE
FREO DATA 90 c -		.
		P C ’		LATCH	P	7
			- 0
	+					J	AMPLITUDE
CLOCK
							MULTIPLIER

Figure 8-2.Simplified Diagram of One Channel of the D WSIC

8-16 Principles of Operation (Overall) rev.lOOCT88