Specifications

2.4.1.7 Low-Pass and High-Pass Op er a tion – [MODE]
When [MODE] is pressed once, DIS PLAY in di cates the pres ent fil ter type, “h.P.” (high-pass) and “L.P.” (low-pass).
When pressed again, the type will change (if the type was “L.P.” , the change will be to “h.P.”).
2.4.1.8 Vari able Band-Pass Op er a tion (Mod els 3382 and 3384 only)
To ob tain Band-Pass op er a tion with 48dB per oc tave at ten u a tion pro ceed as fol lows:
Set chan nel 1 to high-pass mode (this will con trol the low cut off fre quency). Set chan nel 2 to low-pass (this will con trol
the high cut off fre quency). Con nect the in put sig nal to chan nel 1 in put, con nect the chan n el 1 out put to the chan nel 2 in -
put and con nect the load to the chan nel 2 out put. For the Model 3384, the same can be done with chan nels 3 and 4 re spec -
tively.
The min i mum pass-band is ob tained by set ting the high cut off fre quency equal to the low cut o ff fre quency. In this con di -
tion the in ser tion loss is nom i nally 6dB (in the Butterworth mode) and the –3dB cut off fre quen cies oc cur at 0.8 and 1.25
times the mid-band fre quency. In ser tion loss may be made-up by set ting out put gains to +6dB.
2.4.1.9 Vari able Band-Re ject Op er a tion (Mod els 3382 and 3384 only)
To ob tain Band-Re ject or Notch op er a tion, pro ceed as fol lows:
Con nect the two chan nels in par al lel by con nect ing the in put sig nal to the in put of each c han nel si mul ta neously. The out -
put from both chan nels should be added through two equal ex ter nal re sis tors in se ries with each out put. The junc tion of
these re sis tors be comes the out put of the fil ter. It is rec om mended that the re sis tors be ap prox i mately 1k ohms and of the
car bon or metal film type if the fil ter is used at higher fre quen cies. If the two re sis tors are not equal, the gain on one side
of the notch will be dif fer ent than the gain of the other. In ser tion loss may be made-up by set ting out put gains to +6dB.
Set chan nel 1 for low-pass and chan nel 2 for high-pass, and ad just the cut off of each chan nel for the max i mum re jec tion.
The ideal notch oc curs when set ting the low cut off (low-pass) to 0.5 and the high cut off (high-pass) to 1.5 notch. In ser -
tion loss may be made-up by set ting out put gains to +6dB.
Cau tion: Do not ex ceed spec i fied volt age at ter mi nals.
2.4.1.10 AC/DC Cou pling
Press ing the [SHIFT] key, fol lowed by the [TYPE] key, will dis play the pres ent in put cou pling, in di cat ing “AC” or
“dC”. Press [SHIFT] [TYPE] again to tog gle be tween AC and DC.
2.4.1.11 Dif fer en tial/Sin gle-Ended In put
LED in di ca tors are pro vided on the front panel to in di cate which in put(s) is (are) ac tive. Press ing [SHIFT] and then the
[+ONLY] key un der the In put Gain Dis play will se lect sin gle-ended in put mode, only the LED be side the +In put of the
se lected chan nel will be lit. Press ing [SHIFT] and then the [DIFF] key, will se lect the dif fer en tial in put mode and both
LEDs be side the se lected chan nel will be lit.
2.4.1.12 Stor ing a Fil ter Setup – [STORE]
There are 9 stor age lo ca tions for stor ing front panel fil ter set ups. The lo ca tions are num bered 0 through 8. When
[SHIFT] [RECLL][STORE] is first pressed, the DIS PLAY in di cates the num ber of the next mem ory lo ca tion avail able.
For ex am ple, the DIS PLAY will in di cate the fol low ing: “n=05”. Press ing [RECLL] again will store the en tire fil ter
set-up into that mem ory lo ca tion. If an other mem ory lo ca tion is de sired, en ter that lo ca tion on the key board and then
press [SHIFT] [RECLL].When [SHIFT] [RECLL] is pre ceded by a num ber (0-8), the 3380 will store the cur rent fil ter
set-up into the mem ory lo ca tion se lected.
When [SHIFT] [RECLL] is pressed to in di cate the next mem ory lo ca tion only, press ing the clear en try key [CE] will re -
store the DIS PLAY to the cut off fre quency set ting. The fil ter set tings stored in mem ory lo c a tion 0 is au to mat i cally re -
called at turn-on.
Section 2 - Operation Model 3380 Series
2-4