Compaq M-LVDS manual Typical Cable Test Configurations, 1. EVM Configuration Options

Typical Cable Test Configurations

2.1 Typical Cable Test Configurations

Each of the following test configurations is a transmission line consisting of a twisted-pair cable connected on the 2-pin connectors (P1, P2, or P3). Table 2−1 shows the possible configurations.

In addition to the different transmission topologies, the EVM can also be configured to run off two or three separate power supplies, as described in the previous section. This would allow the user to induce a ground shift or offset between the two different drivers and receivers. This setup can be used with any transmission line test.

Table 2−1. EVM Configuration Options

Configuration	Jumpers In	Resistors In	Resistors Out	Diagram
Point-to-point simplex transmission	W1, 2, 7, 8, 9, 10	R4	R5, 6, 7	Figure 2−1
Point-to-point parallel terminated simplex	W1, 2, 7, 8, 9, 10	R4, 7	R5, 6	Figure 2−2
transmission
Two-node multipoint transmission	W1, 2, 3, 4, 7, 8, 9, 10	R5, 16	R2, 4, 6, 7, 13 15	Figure 2−3

2.1.1Point-to-Point Simplex Transmission

1)Connect a twisted-pair cable from P1 to P2.

2)Verify resistor R4 is installed.

3)Remove resistors R5, R6, and R7. This properly terminates the transmission line at one end.

4)Enable the driver by connecting the jumper on W2 between pin 1 and pin 2, or U1 pin 4 to VCC.

5)Enable the receiver by connecting the jumper on W1 between pin 2 and pin 3, or U1 pin 3 to GND.

Figure 2−1. Point-to-Point Simplex Transmission

VCC

Signal Source

with 50-Ω

Output

50-Ω

Cable

J2

TP2

	Jumper
Input Signal	W2
4	9
5
	R7	P2	R6
U1	100		100
R3
	10
49.9			Twisted Pair Cable

			50-Ω		R2
50-	Ω	cable or	Cable	J1			12
					453 2
						U1	R4
Active Voltage							100
Probe into one						3
					TP1		11
Channel of Scope							VCC
Terminated in
High Impedance							W1
				Output Signal
			Active Voltage				Jumper
			Probe

P1	R5
	100

2-2 Test Setup