Quanta Computer HFSWM100, Отчет испытаний ЭМИ

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ETC Report No. : ET90S-11-032 Sheet 33 of 104 Sheets
FCC ID. : HFSWM100
Rev. No 1.0
11 PROCESSING GAIN MEASUREMENT
11.1 Standard Applicable
According to 15.247(e), the processing gain of a direct sequence system shall be at least 10
dB. The processing gain shall be determined from the ratio in dB of the signal to noise ratio
with the system spreading code turned off to the signal to noise ratio with the system
spreading code turned on, as measured at the demodulated output of the receiver.
11.2 Measurement Description
The processing gain measurement is based upon the CW jamming margin method
suggested in the FCC document entitled “GUIDANCE ON MEASUREMENTS FOR
DIRECT SEQENCE SPREAD SPECTRUM SYSTEMS, 54597, July 12,1995”
The test consists of stepping a CW signal generator in 50KHz increment across pass band
of each three channels within 2400 – 2483 MHz band. This CW signal represents the
jamming signal. The selected three channels are as followings:
Channel 01: centered at 2412 MHz
Channel 06: centered at 2437 MHz
Channel 11: centered at 2462 MHz
These three channels represents the Low, Mid and High frequency bands of the EUT,
respectively. And, the processing gain of the EUT determined for these bands should be
representative of the entire band.
(1). Measurement Configuration
The measurement configuration (draw in next page) is according to FCC document
54797,page3.
(2) Derivation of the Processing Gain
(a) The Processing Gain (Gp) is calculated according to the following equations:
Gp=(S/N)o + Mj + Lsys …..(4-1)…. Refer to FCC document 54797 Page3
Where Mj = J/S ratio (dB)
Lsys =System losses (assumed to be 2 dB)
(S/N)o = the required signal to noise ratio at the receiver output for a given
received signal quality
Therefore, from equation (4-1)
Gp=16.4 + J/S +2 (dB) = 18.4 + J/S (dB)…..(4-2)