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equipment:sig-gens [2016/06/03 14:53]
tggzzz
equipment:sig-gens [2020/02/14 13:15]
tggzzz
Line 1: Line 1:
 ===== Signal Generators ===== ===== Signal Generators =====
  
 +==== Simple Audio ====
 There are several simple sine/triangle/square wave signal generators, with adjustible peak-to-peak voltage and voltage offset and duty cycle / symmetry. Their main use is for audio frequencies circuits and mechantronic circuits.  There are several simple sine/triangle/square wave signal generators, with adjustible peak-to-peak voltage and voltage offset and duty cycle / symmetry. Their main use is for audio frequencies circuits and mechantronic circuits. 
  
-Frequency range is up to a couple of %%MHz%%, but at those frequencies the waveform is less than perfect. The front panel controls give an indication of the operating frequency, but if accuracy is required then measure it with a scope or the [[frequency-counters|frequency counter]]. +Frequency range is up to a couple of %%MHz%%, but at those frequencies the waveform is less than perfect. With most, the front panel controls give a vague indication of the operating frequency, but if accuracy is required then measure it with a scope or the [[frequency-counters|frequency counter]]. The Levell contains its own internal frequency meter.
  
-The sig gens are all based around the classic ICL8038, which is effectively a 555 timer with some wave shaping. Consequently the sine waves are noticably distorted at the peaks, and they are unsuitable for serious audiophile purposes.{{ :test_equipment:siggen8038.jpg?direct&200 |}}+The sig gens are all based around the classic ICL8038, which is effectively a 555 timer with some wave shaping. Consequently the sine waves are noticably distorted at the peaks, and they are unsuitable for serious audiophile purposes. 
 + 
 +{{test_equipment:siggen8038.jpg?direct&200}} {{test_equipment:siggen-levell.jpg?direct&200}} {{test_equipment:siggen-peakSpike.jpg?direct&200}} 
 + 
 + 
 +==== RF ==== 
 + 
 +For higher frequencies and when simple modulation is required, we have a Philips PM5390S. The key characteristics are: 
 +  * 100kHz - 1000MHz 
 +  * 50ohm output. At these frequencies 50ohm coax and 50ohm terminations are required if the amplitude is to be correct 
 +  * accurate synthesised frequency and frequency sweeps 
 +  * AM and FM modulation. The internal modulation is inflexible and sufficient for testing/simulating traditional old-school radios. External modulation could be used for more demanding purposes, but I doubt those are relevant at Hackspace 
 + 
 +A quick play with it indicates  
 +  * it is basically functional 
 +  * since it is complex, it is useful to RTFM before using it! 
 +  * it feels as if the internal attenuator or relays need cleanin 
 +  * it looks like it could benefit from recapping the PSU 
 + 
 + 
 +{{test_equipment:philips-pm5390s.jpg?direct&200}}  
 + 
 +Unmodulated sine wave: {{test_equipment:philips-pm5390s-sine.jpg?direct&200}}  
 + 
 +FM: {{test_equipment:philips-pm5390s-fm1.jpg?direct&200}}  
 + 
 +AM: {{test_equipment:philips-pm5390s-am1.jpg?direct&200}} {{test_equipment:philips-pm5390s-am2.jpg?direct&200}}  
 + 
 + 
 + 
 +==== TV Pattern Generator / RF ==== 
 + 
 +We have a PAL/NTSC TV pattern generator with outputs: 
 +  * SCART 
 +  * composite video 
 +  * RF, carrier frequency from 38-890MHz, which covers the IF, VHF and UHF bands. Can set channel or frequency 
 + 
 +It is unlikely that those "obsolete" TV signals will be useful, so the main use of the device is likely to be: 
 +  * a "complex" waveform useful when learning how to use an oscilloscope 
 +  * an RF signal generator, albeit only a modulated signal not a sine wave 
 +  * when testing an old TV or monitor 
 + 
 +{{test_equipment:siggen-tvPattern.jpg?direct&200}}
  • equipment/sig-gens
  • Last modified: 22 months ago
  • by tggzzz