North Hills™Signal Processing

ISO 9001:2000 Certified

A Porta Systems Company

RLB Series - Return Loss Bridges
for UTP and Balanced Systems
In communication circuits, maximum power transfer occurs
when source and load impedance are matched. By relating
it to a reference source impedance, the magnitude of a load
impedance may, meaningfully, be expressed as “return loss.”*Patent Pending

North Hills Series RLB Return Loss Bridges interface with
network analyzers to measure return loss of UTP cable andother balanced systems. There are models for balanced
reference impedances from 100 to 150 ohm for either 50 or75 ohm network analyzers, covering frequency ranges from
10kHz to 300MHz.
There is also a companion RLC Series of Return LossBridges for 50, 75, and 93 ohm coax reference impedances
and a RLT Series for twiaxial networks.
Application Note 155 explains the meaning of return loss
and includes formulas and tables relating impedance, return
loss, reflection factor and transmission losses.
Application Note 157 is a tutorial on return loss bridges.

The North Hills RLB Series Return Loss Bridge

Features:Benefits:••••••

Excellent Bridge directivity
Frequency range 0.01 to 300 MHz
100, 110, 120, 135 and 150 ohm 			balanced impedances available
Other impedances available upon request•

Ideal for UTP cable measurements
Easy interface with 50 or 75 ohm 			network analyzers
Excellent directivity across a broad 		frequency range

Test Procedure:
Step 1:Plug the bridge input directly into the Network 		
Analyzer Output.

Step 2:

Apply the bridge reflected signal output to the 		Network Analyzer input through a cable of impedance
equal to that of the Network Analyzer.

North Hills™Signal Processing
A Porta Systems CompanyStep 3:

With test port open, normalize display to 0 dB.

Step 4:

Terminate the test port with the test load and 			measure return loss directly.

6851 Jericho Turnpike, Suite 170		
Syosset, NY 11791			

Phone:
Fax:

516-682-7740
516-682-7704

A Leading Provider of Measurement and Connectivity Solutions
www.northhills-sp.com

RLB SERIES - RETURN LOSS BRIDGES
Designed to facilitate the measurement of return loss in conjunction with a network
analyzer.

Typical Characteristics - Model 51100RLB:
Mechanical Specifications:
Connectors:

N typeSocket Terminals:

For ø.040 inch (18 GA.) PIN

Case/Cover Material: Aluminum Alloy 6061-T6
Weight:

110 grams (3.9 oz) Typical

Bridge Directivity [dB]    0Unless otherwise specified-20-40-60-80

10 kHz			

30 MHzFrequency [Hz]
.10”
1.20”
.20”
.15”

Ordering Information:
Impedanceohm

Network Analyzers
50 ohmPart#75 ohm
Part#

10kHz-30MHz
1.76”

1.00”

Figure 1. Return Loss Bridge Dimensions

100

51100RLB

71100RLB

110

51110RLB

71110RLB

120

51120RLB

71120RLB

135

51135RLB

71135RLB

150

51150RLB

71150RLB

0.1-100MHz
Network Analyzer
OutSourceINRLB
Test Port

Reflection
Signal

DUT

Fig. 2. Return Loss Bridge Measurement Circuit

North Hills™Signal Processing
A Porta Systems Company

100

52100RLB

72100RLB

110

52110RLB

72110RLB

120

52120RLB

72120RLB

135

52135RLB

72135RLB

150

52150RLB

72150RLB

1-300MHz100

53100RLB

73100RLB

110

53110RLB

73110RLB

120

53120RLB

73120RLB

135

53135RLB

73135RLB

150

53150RLB

73150RLB

Specifications subject to change without notice6851 Jericho Turnpike, Suite 170		
Syosset, NY 11791			

Phone:
Fax:

516-682-7740
516-682-7704

A Leading Provider of Measurement and Connectivity Solutions
www.northhills-sp.com
NH-INS-DAT-10X.06