NDC comm HWB3163 manual Test Point E Test Points F and G, Test Points H

	Application Note 9864
Test Point E	Test Points F and G
RF Transmit Signal:	RF local oscillator (LO):

FIGURE 7. TRANSMITTED 2.4GHz SIGNAL SPECTRUM (TEST POINT E)

The optional SMA connector can be used to hook up a Spectrum Analyzer for RF evaluation. Note that L4 (1.5nH) must be removed and C141 (15pF) and C37 (150pF) must be installed to activate the connector See (Figure 3).

This is the up-converted spread spectrum output of the card. The center frequency of this signal is 2412-2484MHz depending on the channel of operation. The output power of the signal is approximately +12.5dBm. The peaks of the sidelobes of the output spectrum (i.e., the regrowth) are normally adjusted by the ALC/AGC to be 30dB below the peak of the spectrum per requirements of IEEE 802.11.

The following table delineates the IEEE 802.11 channels and their corresponding center frequencies. Although information contained in Table 1 is deemed to be accurate, local regulatory authorities should be consulted before using such equipment.

TABLE 1. IEEE 802.11 CHANNELS

CHANNEL	CHANNEL	GEOGRAPHIC
NUMBER	FREQUENCY	USAGE
1	2412MHz	US, CA, ETSI
2	2417MHz	US, CA, ETSI
3	2422MHz	US, CA, ETSI
4	2427MHz	US, CA, ETSI
5	2432MHz	US, CA, ETSI
6	2437MHz	US, CA, ETSI
7	2442MHz	US, CA, ETSI
8	2447MHz	US, CA, ETSI
9	2452MHz	US, CA, ETSI
10	2457MHz	US, CA, ETSI, FR, SP
11	2462MHz	US, CA, ETSI, FR, SP
12	2467MHz	ETSI, FR
13	2472MHz	ETSI, FR
14	2484MHz	Japan†

KEY: US = United States, CA = Canada, ETSI = ETSI countries (except France and Spain), FR = France, SP = Spain.

†In Japan, authorization for Channels 1 through 11 is pending.

FIGURE 8. RF LOCAL OSCILLATOR OUTPUT AT CHANNEL 8 (TEST POINT F)

The behavior of the RF VCO can be monitored at Test Point F.

The VCO output should be locked at the channel frequency minus the IF (374MHz.) This means that the VCO will have to lock between 2038MHz and 2110MHz. The output power at test point F is approximately -6dBm. Ideally, the tuning voltage of the VCO, when locked, falls between 0.5V and 2.2V. The tuning voltage of the RF VCO can be observed at Test Point G.

Test Points H and I

IF local oscillator (LO):

FIGURE 9. IF LOCAL OSCILLATOR OUTPUT (TEST POINT H)

The IF VCO is a discrete design and operates at 748MHz (i.e., twice the IF frequency). The output frequency of this VCO does not need to be varied; thus, minimal tuning range is required.

The output frequency of this VCO can be observed at Test Point H.

Ideally, the tuning voltage of the IF VCO, when locked, falls between 0.5V and 2.2V. The tuning voltage of the IF VCO can be observed at Test Point I.

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