JP2000287139A - Navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive navigation system by eliminating the need for an exclusive circuit and using a conventional microcomputer thereby to realizing channel searching and sound muting. SOLUTION: A filter 14 extracts a vertical synchronizing signal from a composite video signal outputted from a television tuner 11 and gives the vertical synchronizing signal to an interrupt input terminal of a conventional microcomputer 13 so as to allow the conventional microcomputer 13 to discriminate the presence of a receptible station and whether or not voice muting is to be conducted depending on a degree of stability of a period of the vertical synchronizing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device having a television receiving function.

[0002]

2. Description of the Related Art In recent years, with the spread of car navigation devices, devices having a television receiving function have been required.

Hereinafter, a conventional car navigation device will be described with reference to the drawings.

FIG. 3 is a configuration diagram of a conventional car navigation device.

In FIG. 3, 1 is a television tuner, 2 is a filter for extracting a horizontal synchronizing signal, 3 is a counter for counting the horizontal synchronizing signal, 4 is a register for holding a counter value, and 5 is a counter 3 to a register 4 , A microcomputer for controlling the TV tuner 1, an audio control unit 7 for amplifying and outputting an audio signal output from the TV tuner 1, and 8 for positioning and map drawing. It is a navigation block that realizes a central function as a car navigation device of a user interface.

[0006] The operation of the conventional car navigation device configured as described above will be described below.

The microcomputer 6 instructed by the navigation block 8 to perform a channel search first sets the television tuner 1 to one channel. If there is a receivable station in one channel, an accurate horizontal synchronizing signal appears every 63.5 μs in the composite video signal output from the TV tuner 1,
This causes the counter 3 to operate through the filter 2.
The value of the counter 3 is transferred to the register 4 exactly every 2 ms by the timing generation circuit 5, and the counter 3 is reset. The microcomputer 6 can read the register 4 at an arbitrary timing and detect the number of pulses of the horizontal synchronizing signal for 2 msec. If this value is within the specified range, it is determined that there is a receivable station. If it is out of the prescribed range, it is determined that there is no receivable station. Next, the microcomputer 6 sets the television tuner 1 to two channels, determines whether there is a station capable of receiving the same operation, and repeats this for up to 62 channels, thereby implementing a channel search operation.

The audio mute operation will be described below. If the TV reception has a sufficient electric field strength and the sound is clear, the pulse number of the horizontal synchronizing signal for 2 ms is stabilized as in the channel search, and the microcomputer 6 permits the sound output by the sound control unit 7. I do. However, when the electric field strength is reduced and the noise which is tactile to the voice is generated, the pulse number of the horizontal synchronizing signal for 2 ms becomes unstable, so that the microcomputer 6 reads the value of the register 4 and out of the specified range. Is confirmed, and the sound output by the sound control unit 7 is prohibited.

[0009]

However, in the above conventional configuration, the counter 3 for counting the horizontal synchronizing signal, the register 4 for holding the value of the counter 3, and the timing generation circuit for controlling the transfer from the counter 3 to the register 4 are provided. However, there is a problem that a dedicated circuit composed of 5 is required and the cost is increased.

An object of the present invention is to provide a navigation device at low cost in view of the above-mentioned conventional problems.

[0011]

In order to solve the above-mentioned conventional problems, the present invention uses a general-purpose microcomputer having a counter / timer function and an interrupt function, and further comprises a filter for extracting a vertical synchronizing signal. A car navigation device can be provided at a low cost.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a television tuner for selecting a channel by electrical control, and a filter for extracting a specific frequency component from a composite video signal output from the television tuner. A general-purpose microcomputer connected to the output of the filter and controlling the television tuner, and checking the output signal of the filter with the general-purpose microcomputer to perform a channel search for a receivable station. The feature is that it has a function that a channel search can be performed by a general-purpose microcomputer.

According to a second aspect of the present invention, in the first aspect, the filter extracts a vertical synchronizing signal, and the general-purpose microcomputer generates an interrupt based on the vertical synchronizing signal. The cycle of the vertical synchronizing signal is inspected by using a timer built in the general-purpose microcomputer, and has an operation of realizing a channel search only by the general-purpose microcomputer.

According to a third aspect of the present invention, in the first aspect, the filter extracts a horizontal synchronizing signal, and the general-purpose microcomputer counts the horizontal synchronizing signal by a built-in counter. Then, the value of the counter is read out by an interrupt at a fixed period, and if the value meets specified conditions, the station can be received. Channel search and audio mute are performed only by a general-purpose microcomputer. It has the effect of realizing.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the general-purpose microcomputer is provided separately from a circuit block for realizing a central function as a car navigation device for positioning and map drawing. The channel search and the audio mute are realized only by the general-purpose microcomputer.

According to a fifth aspect of the present invention, there is provided a television tuner for selecting a channel by electrical control, a filter for extracting a specific frequency component from a composite video signal output from the television tuner, The general-purpose microcomputer connected to an output and controlling the TV tuner, and an audio control unit configured to amplify and output an audio signal output from the TV tuner, and inspect an output signal of the filter with the general-purpose microcomputer. By doing so, audio mute is performed, and has the effect that audio mute can be performed by a general-purpose microcomputer.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the filter extracts a vertical synchronizing signal, and the general-purpose microcomputer generates an interrupt with the vertical synchronizing signal. The cycle of the vertical synchronizing signal is inspected by using a timer built in the general-purpose microcomputer, and has an effect of realizing audio mute only by the general-purpose microcomputer.

According to a seventh aspect of the present invention, in the fifth aspect, the filter extracts a horizontal synchronizing signal, and the general-purpose microcomputer counts the horizontal synchronizing signal by a built-in counter. Then, the value of the counter is read out by an interrupt at a fixed period, and if the value meets specified conditions, the station can be received. Channel search and audio mute are performed only by a general-purpose microcomputer. It has the effect of realizing.

According to an eighth aspect of the present invention, in the fifth aspect of the invention, the general-purpose microcomputer is provided separately from a circuit block for realizing a central function as a car navigation device for positioning and map drawing. The channel search and the audio mute are realized only by the general-purpose microcomputer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of a car navigation apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 11 denotes a television tuner;
Is a filter for extracting a vertical synchronizing signal from a composite video signal, 13 is a general-purpose microcomputer, 14 is an audio control unit that amplifies and outputs an audio signal output from the TV tuner 11, and 15 is car navigation for positioning, map drawing, and user interface. It is a navigation block that realizes the central function as a device.

The operation of the car navigation device configured as described above will be described below.

The general-purpose microcomputer 13 instructed to perform a channel search from the navigation block 15 first sets the television tuner 11 to one channel. If there is a receivable station on one channel, an accurate vertical synchronizing signal appears every 16.7 ms in the composite video signal output from the television tuner 11, passes through the filter 12, and enters an interrupt signal of the general-purpose microcomputer 13. Input to terminal. The general-purpose microcomputer 13 reads an internal timer for each interrupt, and determines that there is a receivable station if the value is within a specified range, and determines that there is no receivable station if the value is outside the specified range. I do.
Next, the general-purpose microcomputer 13 sets the TV tuner 11 to two channels, determines whether there is a station that can receive the same operation, and repeats this for up to 62 channels, thereby implementing a channel search operation.

The audio mute operation will be described below. When the TV reception has a sufficient electric field strength and the sound is clear, the number of pulses of the horizontal synchronization signal for 2 ms is stabilized as in the channel search, and the general-purpose microcomputer 13 controls the sound output by the sound control unit 14. To give permission. However, when the electric field strength is reduced and the noise which is tactile to voice is generated, 2
Since the number of pulses of the horizontal synchronizing signal during m seconds becomes unstable, the general-purpose microcomputer 13 reads the value of the built-in register, confirms that the value is outside the specified range, and outputs the sound by the sound control unit 14. Ban.

As described above, according to the present embodiment, a dedicated circuit is unnecessary, a channel search operation and a sound mute operation are realized using a general-purpose microcomputer, and an effect that a low-cost car navigation device can be provided. .

(Embodiment 2) FIG. 2 is a configuration diagram of a car navigation system according to a second embodiment of the present invention. In FIG. 2, 21 is a television tuner, 22 is a filter for extracting a horizontal synchronizing signal from a composite video signal, 23 is a general-purpose microcomputer, 24 is an audio control unit that amplifies and outputs an audio signal output from the television tuner 21,
Reference numeral 25 denotes a navigation block that realizes a central function as a car navigation device for positioning, map drawing, and user interface.

The operation of the car navigation device configured as described above will be described below.

The general-purpose microcomputer 23 instructed by the navigation block 25 to perform a channel search first sets the television tuner 21 to one channel. If there is a receivable station on one channel, an accurate vertical synchronizing signal appears every 63.5 μs in the composite video signal output from the television tuner 21, passes through the filter 22, and enters the counter input terminal of the general-purpose microcomputer 23. Is input to The general-purpose microcomputer 23 reads the value of the counter at a constant cycle by generating an interrupt using an internal timer. The general-purpose microcomputer 23 determines that there is a receivable station if the value of the counter is within the specified range, and determines that there is no receivable station if the value of the counter is out of the specified range.

Next, the general-purpose microcomputer 23 is connected to the TV tuner 2.
1 is set to 2 channels, it is determined whether or not there is a station that can be received by the same operation, and this is repeated up to 62 channels to realize a channel search operation.

The audio mute operation will be described below. When the television reception has a sufficient electric field strength and the sound is clear, the pulse number of the horizontal synchronizing signal for 2 ms is stabilized similarly to the channel search, and the general-purpose microcomputer 23 controls the sound output by the sound control unit 24. To give permission. However, when the electric field strength is reduced and the noise which is tactile to voice is generated, 2
Since the number of pulses of the horizontal synchronizing signal during m seconds becomes unstable, the general-purpose microcomputer 23 reads the value of the built-in register, confirms that the value is outside the specified range, and outputs the sound output by the sound control unit 24. Ban.

As described above, according to the present embodiment, a channel search operation and an audio mute operation are realized by using a general-purpose microcomputer without using a dedicated circuit, and an effect that a low-cost car navigation apparatus can be provided. .

[0033]

According to the present invention, since a dedicated microcomputer is not required and a general-purpose microcomputer is used, a low-cost car navigation device can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a car navigation device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a car navigation device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional car navigation device.

[Explanation of symbols]

 11 TV tuner 12 Filter 13 General purpose microcomputer 14 Voice control unit 15 Navi block

Continued on the front page F term (reference) 2F029 AA02 AC02 AC14 AC18 5C025 AA24 AA28 BA09 BA13 DA07 DA10 5H180 AA01 FF25 FF27 FF32 5J103 AA01 CB05 DA16 DA26 GA11 9A001 BB02 BB03 BB04 HH15 HH16 KK11 JJ19 KK37

Claims (8)

[Claims] 1. A television tuner for selecting a channel by electrical control, a filter for extracting a specific frequency component from a composite video signal output from the television tuner, and a control connected to an output of the filter and controlling the television tuner. And a channel search for a receivable station by inspecting the output signal of the filter with the general purpose microcomputer. 2. The filter extracts a vertical synchronizing signal, the general-purpose microcomputer generates an interrupt by the vertical synchronizing signal,
2. The station according to claim 1, wherein a period of the vertical synchronizing signal is checked using a timer built in the general-purpose microcomputer for each interrupt, and if the period meets a prescribed condition, the station can be received. The navigation device according to claim 1. 3. The filter extracts a horizontal synchronizing signal, the general-purpose microcomputer counts the horizontal synchronizing signal by a built-in counter, and reads out the value of the counter by an interrupt of a fixed period, and the value is set to a specified value. 2. The navigation apparatus according to claim 1, wherein the station is a receivable station if the conditions are met. 4. The navigation device according to claim 1, wherein the general-purpose microcomputer is provided separately from a circuit block that realizes a central function as a navigation device for positioning and map drawing. 5. A television tuner for selecting a channel by electric control, a filter for extracting a specific frequency component from a composite video signal output from the television tuner, and a control for controlling the television tuner connected to an output of the filter. The general-purpose microcomputer that performs the above, comprises an audio control unit that amplifies and outputs an audio signal output from the television tuner, and performs an audio mute by inspecting the output signal of the filter with the general-purpose microcomputer. A featured navigation device. 6. The filter extracts a vertical synchronizing signal, the general-purpose microcomputer generates an interrupt based on the vertical synchronizing signal,
6. The navigation according to claim 5, wherein a cycle of the vertical synchronizing signal is checked using a timer built in the general-purpose microcomputer for each interrupt, and the sound is muted if the cycle does not meet a prescribed condition. apparatus. 7. The filter extracts a horizontal synchronizing signal, the general-purpose microcomputer counts the horizontal synchronizing signal by a built-in counter, reads out the value of the counter by an interrupt of a fixed period, and sets the value to a specified value. The navigation device according to claim 5, wherein the sound is muted if the condition is not met. 8. The navigation device according to claim 5, wherein the general-purpose microcomputer is provided separately from a circuit block that realizes a central function as a navigation device for positioning and map drawing.