PURPOSE OF THE EQUIPMENT The Model 142 HF VCG Generator provides sine, square, triangle, positive pulse, and negative pulse outputs (with a separate sync output) over a 0.0005 Hz to 10 MHz frequency range. Frequency range selection is provided in ten decades; and a vernier control permits adjustment to within approximately 1% of the range selected. The symmetry of any output waveform is continuously adjustable from 1:19 to 19:1 (5%-95% to 95%-5%). Pulse outputs as narrow as 50 nanoseconds having repetition rates as high as 1 MHz {on-off ratio as great as 19:1} can be generated in either polarity. Varying the symmetry of the triangle function will produce a sawtooth or "ramp" signal with a rise or fall rime as steep as 50 nanoseconds at a recurring rate of 1 MHz, Even the symmetry of the sine wave may be varied over this 1:19 to 19:1 range if desired. When the symmetry control is used, however, the indicated frequency is divided by a factor of approximately 10, A VCG input allows the output to be frequency modulated, dc programmed, or swept over a 1000:1 ratio. The dc offset of the 30V p-p maximum signal output can be controlled manually or electronically. A 60 dB calibrated step attenuator and a 20 dB vernier provide an overall attenuation of 80 dB; permitting signal levels as low as 1.5 mV p-p. Both the output waveform and the dc offset are attenuated by the 60 dB step attenuator. With this instrument it is possible to simultaneously program and sweep the output frequency, select the output symmetry desired, and manually or electronically vary the dc offset. This capability, coupled with the variety of waveforms available and precision output amplitude control, makes the Model 142 an extremely versatile instrument for engineering, manufacturing, and laboratory applications.