HC5526

FN4151 Rev 8.00

Page 17 of 19

August 2003

11. Two-Wire Return Loss.

The 2-wire return loss is computed using

the following equation:

r = -20

 log (2VM/VS),

where: ZD = The desired impedance; e.g., the characteristic

impedance of the line, nominally 600

(Reference Figure 6).

12. Overload Level (4-Wire port).

The overload level is specified at the

4-wire transmit port (VTXO) with the signal source (EG) at the 2-

wire port, IDCMET =23mA, ZL = 20k (Reference Figure 7).

Increase the amplitude of EG until 1% THD is measured at VTXO.

Note that the gain from the 2-wire port to the 4-wire port is equal to 1.

13. Output Offset Voltage.

The output offset voltage is specified with

the following conditions: EG = 0, IDCMET = 23mA, ZL =  and is

measured at VTX. EG, IDCMET, VTX and ZL are defined in Figure

7. Note: IDCMET is established with a series 600 resistor between

tip and ring.

14. Two-Wire to Four-Wire (Metallic to VTX) Voltage Gain.

The 2-wire

to 4-wire (metallic to VTX) voltage gain is computed using the

following equation.

G2-4 = (VTX/VTR), EG = 0dBm0, VTX, VTR, and EG are defined

in Figure 7.

15. Current Gain RSN to Metallic.

The current gain RSN to Metallic is

computed using the following equation:

K = IM [(RDC1 + RDC2)/(VRDC - VRSN)] K, IM, RDC1, RDC2,

VRDC and VRSN are defined in Figure 8.

16. Two-Wire to Four-Wire Frequency Response.

The 2-wire to 4-

wire frequency response is measured with respect to EG = 0dBm at

1.0kHz, ERX = 0V, IDCMET = 23mA. The frequency response is

computed using the following equation:

F2-4 = 20  log (VTX/VTR), vary frequency from 300Hz to 3.4kHz

and compare to 1kHz reading.

VTX, VTR, and EG are defined in Figure 9.

17. Four-Wire to Two-Wire Frequency Response.

The

4-wire

to

2-wire frequency response is measured with respect to

ERX = 0dBm at 1.0kHz, EG = 0V, IDCMET = 23mA. The frequency

response is computed using the following equation:

F4-2 = 20  log (VTR/ERX), vary frequency from 300Hz to 3.4kHz

and compare to 1kHz reading.

VTR and ERX are defined in Figure 9.

18. Four-Wire to Four-Wire Frequency Response.

The

4-wire

to

4-wire frequency response is measured with respect to

ERX = 0dBm at 1.0kHz, EG = 0V, IDCMET = 23mA. The frequency

response is computed using the following equation:

F4-4 = 20  log (VTX/ERX), vary frequency from 300Hz to 3.4kHz

and compare to 1kHz reading.

VTX and ERX are defined in Figure 9.

19. Two-Wire to Four-Wire Insertion Loss.

The

2-wire

to

4-wire

insertion loss is measured with respect to EG = 0dBm at 1.0kHz

input signal, ERX = 0, IDCMET = 23mA and is computed using the

following equation:

L2-4 = 20  log (VTX/VTR).

where: VTX, VTR, and EG are defined in Figure 9. (Note: The fuse

resistors, RF, impact the insertion loss. The specified insertion loss

is for RF = 0).

20. Four-Wire to Two-Wire Insertion Loss.

The

4-wire

to

2-wire

insertion loss is measured based upon ERX = 0dBm, 1.0kHz input

signal, EG = 0, IDCMET = 23mA and is computed using the following

equation:

L4-2 = 20  log (VTR/ERX).

where: VTR and ERX are defined in Figure 9.

21. Two-Wire to Four-Wire Gain Tracking.

The 2-wire to 4-wire gain

tracking is referenced to measurements taken for EG = -10dBm,

1.0kHz signal, ERX = 0, IDCMET = 23mA and is computed using

the following equation.

G2-4 = 20  log (VTX/VTR) vary amplitude -40dBm to +3dBm, or

-55dBm to -40dBm and compare to -10dBm reading.

VTX and VTR are defined in Figure 9.

22. Four-Wire to Two-Wire Gain Tracking.

The 4-wire to 2-wire gain

tracking is referenced to measurements taken for ERX = -10dBm,

1.0kHz signal, EG = 0, IDCMET = 23mA and is computed using the

following equation:

G4-2 = 20  log (VTR/ERX) vary amplitude -40dBm to +3dBm, or

-55dBm to -40dBm and compare to -10dBm reading.

VTR and ERX are defined in Figure 9. The level is specified at the 4-

wire receive port and referenced to a 600

 impedance level.

23. Two-Wire Idle Channel Noise.

The 2-wire idle channel noise at

VTR is specified with the 2-wire port terminated in 600(RL) and

with the 4-wire receive port grounded (Reference Figure 10).

24. Four-Wire Idle Channel Noise.

The 4-wire idle channel noise at

VTX is specified with the 2-wire port terminated in 600(RL). The

noise specification is with respect to a 600

 impedance level at

VTX. The 4-wire receive port is grounded (Reference Figure 10).

25. Harmonic Distortion (2-Wire to 4-Wire).

The harmonic distortion

is measured with the following conditions. EG = 0dBm at 1kHz,

IDCMET = 23mA. Measurement taken at VTX. (Reference Figure

7).

26. Harmonic Distortion (4-Wire to 2-Wire).

The harmonic distortion

is measured with the following conditions. ERX = 0dBm0. Vary

frequency between 300Hz and 3.4kHz, IDCMET = 23mA.

Measurement taken at VTR. (Reference Figure 9).

27. Constant Loop Current.

The constant loop current is calculated using

the following equation:

IL = 2500 / (RDC1 + RDC2).

28. Standby State Loop Current.

The standby state loop current is

calculated using the following equation:

IL = [|VBAT| - 3] / [RL +1800], TA = 25oC.

29. Ground Key Detector.

(TRIGGER) Increase the input current to

8mA and verify that DET goes low.

(RESET) Decrease the input current from 17mA to 3mA and verify

that DET goes high.

(Hysteresis) Compare difference between trigger and reset.

30. Power Supply Rejection Ratio.

Inject a 100mVRMS signal (50Hz

to 4kHz) on VBAT, VCC and VEE supplies. PSRR is computed using

the following equation:

PSRR = 20

 log (VTX/VIN). VTX and VIN are defined in Figure 12.