Semiconductor device and signal processing method thereof

1. A semiconductor integrated circuit device provided in a chip, comprising:

a first tuner interface adapted to be coupled to a first tuner for receiving a first broadcast wave transferring first content data;

a second tuner interface adapted to be coupled to a second tuner for receiving a second broadcast wave transferring second content data;

a general purpose processor configured to decode a first broadcast signal supplied from the first tuner interface; and

a decoder configured to decode the first broadcast signal and a second broadcast signal supplied from the second tuner interface,

wherein an amount of the first content data transferred per unit time is smaller than that of the second content data,

wherein the general purpose processor and the decoder are configured to decode the first broadcast signal and the second broadcast signal respectively in a same period, and

wherein the general purpose processor has a function of determining which of the first and second broadcast signals the decoder decodes based on a field intensity of the second broadcast wave.

2. The semiconductor integrated circuit device according to claim 1 ,

wherein the general purpose processor starts to decode the first broadcast signal when a field intensity of the second broadcast wave falls below a first threshold level, and

wherein the decoder starts to decode the first broadcast signal when a field intensity of the second broadcast wave falls below a second threshold level which is lower than the first threshold level.

3. The semiconductor integrated circuit device according to claim 2 , wherein each of the first and second threshold levels is variable.

4. The semiconductor integrated circuit device according to claim 3 ,

wherein the general purpose processor is a control processor of an on-board navigation system, and

wherein the first and second threshold levels change according to at least one of weather information, speed information, and position information supplied to the general purpose processor.

5. The semiconductor integrated circuit device according to claim 1 , wherein the first and the second tuners are components of the on-board navigation system.

6. A method of processing broadcast signals in a semiconductor integrated circuit provided in a chip, the method comprising:

(a) receiving a first broadcast wave transferring first content data using a first tuner interface;

(b) receiving a second broadcast wave transferring second content data using a second tuner interface, wherein an amount of the first content data transferred per unit time is smaller than that of the second content data;

(c) outputting a first broadcast signal by the first tuner interface corresponding to the first broadcast wave;

(d) outputting a second broadcast signal by the second tuner interface corresponding to the second broadcast wave;

(e) decoding the second broadcast signal using a decoder;

(f) decoding the first and second broadcast signals using a general purpose processor and the decoder respectively and simultaneously when a field intensity of the second broadcast wave is lower than a first threshold level;

(g) decoding the first broadcast signal using the decoder when a field intensity of the second broadcast wave is lower than a second threshold level which is lower than the first threshold level; and

(h) after said step (g), halting the decoding of the first broadcast signal by the general purpose processor.