Applications

Notch filters are useful in situations where a selected frequency must be attenuated while passing all others. Notch filters are commanly used to:
1. Increase dynamic range of spectrum analyzers.
2. Remove interfering signals in high gain amplifying systems.
3. Remove harmonics or spurious signals from signal sources or low power transmitters to 250 Watts.
4. Use to notch an overloading signal in receivers.
5. Multi-couplers.
Although a small unit physically, the TNF310 offers extremely good insertion loss characteristics. The narrow 3 dB bandwidth allows the filter to be used to notch signals in the same band as the desired signal. For example, an overloading signal on 7370 kHz could be notched while receiving a signal on 7000 kHz.

Application Notes

The use of notch filters to enhance spectrum analyzer measurements is discussed in the application note:
"Spectrum Analyzer measurements"
This note is available for down loading from this website in PDF format.

Description

The TNF310 is designed using carefully chosen parts in the tuned circuit to insure that there are no unwanted disturbances in the pass band which is up to 110 Mhz.. The guarenteed pass band is then specified; this is known as the MUF.
Careful circuit design provides low VSWR; thus, assuring that no unwanted notches of significant level, or any other disturbances, occur from DC to 110 MHz.

Description-continued

By routing the notch filter thru the low pass filter section any parasitic notches from the tuned circuit are suppressed.
The circuits used provide Q balance over each range, thus providing uniform notch depth over the range. (22 dB to 24 dB from low to high.
Because insertion loss is minimal, typically <0.5 dB, a TNF310 may be inserted for each unwanted signal, But when two unwanted frequencies are close together, one TNF310, tuned between the two frequencies, will suppress both signals.
The TNF310 is contained in a heavy-duty nickel plated brass enclosure providing excellent shielding. Stainless steel hardware and nickel plating prevent corrosion from dissimilar metal action. You can expect the unit to yield many years of trouble-free service, even under field conditions..

Quality

To insure that high quality is maintained each unit is thoroughly inspected both mechanically and electrically. All units are aged and then retested to insure superior stability over the lifetime of the instruments.

Availability

These units are normally stock items: 1 week delivery. Special orders or large quantities usually require 2-4 weeks.

Specifications

Please refer to next page for detailed specifications.

SPECIFICATIONS

Electrical

Turning Range:

2-30 MHz in 5 bands

Parasitic Notch:

DC-35 MHz none

35-110 MHz < 1.5 dB

Return Loss:

> 10 dB (2:1VSWR)

Insertion Loss:

<1.0 dB DC-110 MHz

Power:

+54 dBm (250 Watts)

Max Voltage

500 V DC+AC components

Intercept Point

IP3: +84 IP2 +100

Bandwidth(3dB)

See Table

Environmental

Temperature:

+0 to +70C operational
-55 to +125 storage

Humidity:

10-80% RH, non-cond

Shock:

Drop from 1"

Vibration:

100 G any Axis

Waterproof:

No

SPECIFICATIONS-cont

Mechanical

Case Size:

6"x4"x2.5" exclud. connectors

Weight:

< 3.0 lbs

Construction:

Can is of brass .025"; nickel plated per Mil-C-26074. Connectors are stainless steel or brass. All hardware is stainless steel.

Options

Connectors

"BF"

BNC female Standard

"MF"

"NF"

N female Standard

"NM"

N male

Test:

Test data can be provided on pass band and stop band, return loss, and group delay.

TD

Test Data Plots

COC

Certificate of Conformance

Ordering Information

Select the frequency range desired from the table below. The correct part number of the filter will be in the left hand column. Add the correct suffix for the type of connectors desired from Options above. Call the factory or authorized representative to place order.