LA17000M 查看數據表（PDF） - SANYO -> Panasonic

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LA17000M

Tuner System IC with Built-in PLL for Car Audio Applications

SANYO -> Panasonic 

LA17000M

[FM IF Selectivity Switching Circuit]

Features

1) Comprises an FM/AM one-chip system.

2) Up conversion method is adopted for AM.

3) Uses an IF filter with a center frequency that is the same as the middle frequency of FM.

4) Uses a narrowband filter in AM mode.

5) Uses a narrowband filter in FM mode only during SEEK or when there is interference from adjacent frequencies.

6) Uses a wideband filter for normal reception in FM mode.

7) For an RDS AF search, switches to a narrowband filter and detects SD.

8) High sensitivity for detecting interference from adjacent frequencies.

Advantages

1) This FM/AM one-chip tuner system (an IC that includes a microcontroller interface) allows for improved adjacent

frequency interference characteristics without increased cost.

2) Prevents SD and IF count misdetection (station detection) during seek search, RDS AF search, and auto memory

operations.

3) Permits adoption of an IC for certain functions without increasing the number of IC pins.

4) CF selectivity can be switched by the software in the microcontroller that controls the tuner, making it easy to

achieve performance differentiation through the software.

(The software can freely set the CF switching timing and conditions.)

5) Detects the radio wave status in the field through detection of SD, desired station field intensity, IF count output, and

adjacent station field intensity. This IC offers improved adjacent frequency interference characteristics by switching

the CF automatically when interference is being generated from an adjacent frequency.

[IF Band Switching Circuit]

Purpose

This AM/FM one-chip tuner IC automatically switches the FM selectivity, prevents misdetection during SEEK opera-

tions, and offers improved adjacent frequency interference characteristics without any increase in cost.

New Technological Features

1. Comprises an AM/FM one-chip IC.

2. Because the narrowband CF that is used by the AM UP conversion system is also used for FM, additional external

components required by earlier systems can be eliminated.

3. Uses a wideband CF during normal FM reception for high sound quality.

4. Uses a narrowband CF for AM reception, and if interference is being generated from adjacent frequencies during

FM reception.

5. Uses a narrowband CF during SEEK and RDSAF search operations, preventing misdetection of SD and IF count

due to adjacent stations.

6. CF switching is performed at the first IF amp input, and the amp gain is adjusted automatically to a suitable level

according to the CF band form AM/FM or FM.

7. Switching of the CF input and the first IF amp gain is controlled by a microcontroller through the interface. The

pins that are controlled are connected to the I/O ports of the microcontroller, and are controlled by the

microcontroller’s internal software.

8. Detection of adjacent frequency interference during FM reception is based on S-meter output, SD, and IF count

output. The IF count buffer frequency fluctuates when interference is being generated from adjacent frequencies.

This fluctuation is used to make the detection of interference from adjacent frequencies possible. (Related patents

have been applied for.)

Conventional Technologies

1. Comprised of a dedicated IC for IF band switching, or of multiple ICs.

2. None of the AM/FM all-in-one chip systems include the functions provided by the LA17000M.

3. Requires a narrowband CF especially for FM, resulting in increased costs. (Does not share the AM narrowband CF.)

4. Because CF switching control is handled by analog circuits or logic circuits, the switching timing can only be

controlled through uniform conditions. Control by software is not possible.

No. 6522-7/54

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