Function Generator (Wavetek Model 19)
Used in the following activities:
The gray 2MHz Wavetek Sweep/Function Generator (Model 19) is from the 1st and 2nd year labs.
Description
The frequency range is 0.002 Hz to 2MHz selcted by a seven decade range multiplier and calibrated vernier. Both the frequency vernier and the sweep input can control up to 1000:1 frequency change within a selected range.
The generator output level is 20 Vp-p maximum from a 50 ohm source. The level is set via a switched attenuator plus vernier with a total range of 50 dB. DC offset is vernier adjustable over a ±10V range with center detent for 0V. A 9:1 symmetry range permits ramp and pulse waveforms to be produced.
Specifications
| Waveforms | sine, triangle, square, TTL pulse or DC OUT |
|---|---|
| Frequency | 0.002 Hz to 2 MHz (7 ranges) |
| 2: 0.002 to 2 Hz | |
| 20: 0.02 to 20 Hz | |
| 200: 0.2 to 200Hz | |
| 2k: 2 Hz to 2kHz | |
| 20k: 20 Hz to 20 kHz | |
| 200k: 200 Hz to 200 kHz | |
| 2 M: 2 kHz to 2MHz | |
| Internal Sweep Generator | |
| Sweep Range | Up to 1000:1 within each range |
| Sweep Rate | 30 ms to 15 s (typically 20 ms to 20 s) |
| Sweep Mode | Linear or logarithmic. |
| Amplitude Modulation | |
| Modulated by internal 400 Hz oscillator | |
| Precision (Display Accuracy) | |
| Frequency | ±5 digits on 2 kHz to 2MHz ranges |
| <= 1.5% of full scale on 2Hz to 200Hz ranges | |
| Amplitude | Typically 5% of range at 1kHz |
| DX offset | Typically 2% of reading + 100 mV |
| Resolution | 0.05% maximum on all ranges (1 part in 2000) |
| Distortion | less than 1% on 200, 2k and 20k ranges (sine) |
| less than 1.5% on 20 and 200k ranges (sine) | |
| Output Impedence | Source of selected function at 50 ohm |
| Peak Output | 100 mA maximum into 50 Ohm |
Operating Instructions
- Use FREQUENCY RANGE BUTTONS to select the decade range in which your desired frequency appears.
- Adjust the FREQUENCY VERNIER to the required target frequency.
- Observe the display readout and readjust the FREQUENCY VERNIER if necessary until the display matches the target frequency.
- Select a waveform using FUNCTION BUTTONS (sine, square, triangle)
- Skewness of waveform can be obtained by pressing the SYM BUTTON and then adjusting the SYMMETRY control. Monitor the display.
- Adjust the AMPLITUDE control where the display reads twice the desired waveform voltage (ie. a 2 Vp-p sine wave should have AMPLITUDE set to 4 Vp-p).
- Press the DISPLAY SELECT BUTTON to enable the "DC" units indicator. To specify offset, adjust DC OFFSET until the display reads twice the desired offset.
- After setting FREQUENCY RANGE, pull the RATE and STOP controls out to turn on the sweep generator to a LOG vs linear sweep.
- Press and hold SET START while adjusting the FREQUENCY DIAL to the opening range frequency.
- Press and hold SET STOP while adjusting the FREQUENCY DIAL to the closing range frequency.
- Connect SWEEP OUT to a frequency counter to set the waveform period (seconds)
- Connect MAIN OUT to the scope to observe the swept waveform.
Document written June 13, 1996. Original author: Jeremy Bailin and Jaime Espinoza.
