Specifications

3.6 NOISE CHECK
Short the `+’ in puts of both fil ter chan nels and set the chan nel be ing tested to 0dB in put gain, 0dB out put gain, lowpass
(mode key), butterworth (type key), DC cou pled (press shift then type, if dis play shows `AC’ press shift type again; dis -
play will show `DC’). Con nect a 2MHz lowpass, pas sive fil ter, shown in Fig 3.2, to the ac volt m e ter and, us ing a short
coax BNC ca ble, con nect it to the model 3380’s out put. Set the fil ter to 5kHz. Volt me ter read ing should be 400µV or
less. Set the fil ter to highpass (mode key). Volt me ter read ing should be 400µV or less. Set the fil ter to 50kHz, lowpass.
Volt me ter read ing should be 400µV or less. Set the fil ter to highpass. Volt me ter read ing should be 400µV or less. Set in -
put gain to 50dB and out put gain to 20dB (press 20 and ei ther of the out put gain ar rows). Volt me ter should read 80mV or
less.
3.7 COM MON MODE RE JEC TION
Set the fil ter to low-pass, 20kHz cut off and dif fer en tial in put by press ing the shift key, then the DIFF key un der the IN -
PUT GAIN dis play. Set the gen er a tor to 10kHz at 7Vrms. Con nect the gen er a tor to the + and – in puts si mul ta neously.
Con nect the ac volt me ter to the fil ter out put. Read ing should be <7mVrms. Set the fil ter to 200kHz and gen er a tor to
100kHz. AC volt me ter should read <25mVrms.
3.8 DIS TOR TION AND MAX I MUM SIG NAL CHECKS
Set the fil ter to a cut off fre quency of 1kHz in the low-pass mode with 0dB of In put and Out put gain. Con nect a low dis
-
tor tion os cil la tor to the IN PUT and ap ply a 1Vrms sig nal at 1kHz.
CAU TION
If the dis tor tion is ex ces sive, ver ify that the
dis tor tion of the os cil la tor be ing used is <0.005%.
Mon i tor the OUT PUT of the fil ter with a dis tor tion an a lyzer. The read ing should be <0.1%.
Con nect a 50 ohm ter mi na tor to the OUT PUT of the fil ter. Dis tor tion should be <0.1%. Re move the ter mi na tor.
Dis con nect os cil la tor and dis tor tion an a lyzer.
Model 3380 Section 3 - Incoming Acceptance
3-3
Figure 3.2 Passive 2MHz Low-Pass Filter