AT48810
Features
∙Designed for use with Atmel’s AT48802 Spread-Spectrum Signal Processor
∙FCC Part 15, Unlicensed Operation
∙RF Despreading and Narrowband IF for Highest Jamming Margin
∙1 mW Narrowband Operation, or 1 and 50 mW Spread-Spectrum Operation
Description
The AT48810 RF module is intended for time domain duplex spread-spectrum communications under FCC Part 15, 902-928 MHz unlicensed operations. This module features RF despreading and narrowband IF for powerful interference rejection. Spreading is via direct sequence. The unit can also be operated in a narrow-band configuration (FCC limits power to 1 mW in narrow band) by restricting the DC voltage to the power amplifier so that the transmit power is less than 0 dBm per FCC regulations. The unit can also be run in slow half duplex or simplex mode.
Pin Diagram
15.36 MHz Clock Out |
1 |
2 |
Audio Out |
Ground |
3 |
4 |
Ground |
VCC |
5 |
6 |
RSSI Out |
Synthesizer Data Clock Input |
7 |
8 |
T/R Switch |
Synthesizer Data Input |
9 |
10 |
LNA Gain Hi/Low |
Synthesizer Data Latch Input |
11 |
12 |
VCC |
Modulation Input |
13 |
14 |
No Connection |
No Connection |
15 |
16 |
Transmit Power On/Off Input |
PN Spreading Enable Input |
17 |
18 |
Power Amp VCC Input |
PN Input |
19 |
20 |
Power Amp VCC Input |
Note: 1. Connector on module is Dupont/Berg part number 87814-610. Mating connector is 87409-110.
900 MHz
Spread-
Spectrum RF
Module
Preliminary
0625A
3-1
Block Diagram
TX PWR |
ON/OFF |
fC = 83.16 MHz |
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GAIN |
Bw = 30 kHz |
fC = 1.23 MHz |
RSSI |
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LNA |
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IF AMP |
DISCRIMINATOR |
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ANTENNA |
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DOWN |
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3 |
PORT |
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CONVERTER |
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T/R |
XTAL OSC |
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TCXO |
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83.16 ± 1.23 MHz |
SYNTHESIZER |
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SWITCH |
15.36 MHz |
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HANDSET OR BASE |
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902- |
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928 MHz |
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UPCONVERTER |
SPREAD |
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TR SW |
AMP |
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fC = 915 MHz |
ON/OFF |
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TX PWR |
ON/OFF |
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OTHER CIRCUITS |
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PA VCC |
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PN PN ENABLE |
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VCC |
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Note: 1. The module cannot legally be certified without an antenna; this is an FCC requirement.
AUDIO
DATA
CLOCK
TDD Rate
7.5 kHz max
Operating Frequencies
Table 1. Version “B” (1, 2, 3, 4, 5, 6, 7, 8)
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End B |
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Channel |
N |
First LO, MHz |
TX, MHz |
RX, MHz |
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1 |
1334 |
825.7536 |
910.1424 |
908.9136 |
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2 |
1350 |
829.4400 |
913.8288 |
912.6000 |
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3 |
1356 |
833.1264 |
917.5152 |
916.2864 |
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4 |
1363 |
837.4272 |
921.8160 |
920.5872 |
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Note: 1. Second LO = 84.3888 MHz |
6. |
Synthesizer PLL Bandwidth = 80 kHz nominal |
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2. |
Reference Divider = 25 |
7. |
Frequency Accuracy = ±3.5 ppm |
3. |
Phase Detector = 614.4 kHz |
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(including temperature 0° to 50°C) |
4. |
First IF = 83.160 MHz |
8. |
Switching Time = 2.2 ms nominal, Ch 1 to Ch 4 |
5. |
Second IF = 1.229 MHz |
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3-2 |
AT48810 |
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