JPH0529164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic tuning device for a radio receiver having an automatic preset function.

[Technical background of the invention and its problems]

2. Description of the Related Art Radio receivers, for example, in-vehicle radio receivers installed in automobiles, etc., are provided with various functions in order to improve their operation. One of these features is called the auto preset feature or best stations memory (BSM) feature. This auto preset (or BSM) function is
By automatically searching all frequencies within the receiving band, receiving frequencies above a certain level are selected, and the receiving frequency information of the selected stations is stored in advance in a rewritable preset memory in descending order of receiving strength. When broadcasting, the receiving frequency information of the receiving station is read from the preset memory by pressing the tuning button, etc. corresponding to the receiving station, and the tuning frequency of the tuning circuit is automatically set to the read receiving frequency to select the preset station. is to be received.

Conventionally, in a radio receiver equipped with this type of auto-preset function, the means to start the auto-preset operation is to press a preset operation start button provided on the receiver, and then the preset operation is restarted. It was not possible to change the stations stored in the preset memory without pressing the start button and redoing the preset.

Conventional radio receivers select stations as described above, so if the vehicle is traveling a long distance, it may not be possible to receive the preset stations. There was a problem where I had to press the start button or the like and redo the preset. Furthermore, if a preset station is called without knowing the change in reception conditions at the destination, there is a risk that only noise will be heard.

[Purpose of the invention]

The present invention was made to solve the above problem, and it monitors the input electric field strength of a preset station, and when it drops below a certain level, automatically replaces it with another station with a higher input electric field strength. The present invention provides an automatic tuning device for a radio receiver that automatically presets channels.

[Summary of the invention]

In order to achieve the above object, the present invention provides a radio receiver equipped with an auto preset function.
A field strength level setting circuit that sets a reference input field strength, and a field strength measurement control circuit that automatically instructs to measure the input field strength of receiving stations stored in a preset memory at predetermined intervals over all stations. If there is a station whose input level is lower than the reference input field strength set in the field strength level setting circuit among the preset receiving stations,
The auto preset function is activated to automatically preset a new station having an input level equal to or higher than the reference input electric field strength in place of the preset station with a low input level, so that the best receiving station in the area is always selected. It looks like it's preset.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the configuration of an embodiment of an automatic tuning device according to the present invention, in which 1 is a receiving section equipped with an electronic tuning type tuning circuit such as a PLL synthesizer system, and 2 is a frequency control/tuning station of the receiving section 1. A control unit that performs detection (SD) sensitivity control, etc., 3 a storage unit consisting of a preset memory etc. that stores preset frequency information of the receiving station, etc., 4 converts the electric field strength (SL) of the receiving station into a digital signal. 5 is a field strength level setting circuit for setting a reference input field strength for reception; 6 is a timer 7 for a certain period of time;
This is a field strength measurement control circuit that issues an instruction to measure the input field strength to the control unit 2 in accordance with a clock given every 10 minutes, for example, and starts the automatic channel selection operation of the present invention.

The operation of the embodiment of the present invention having the above configuration will be explained with reference to the flowchart shown in FIG. It is assumed that the preset memory in the storage unit 3 has already been preset with, for example, a plurality of stations that are received in the area where the vehicle equipped with the radio receiver is permanently stationed.

When control is started by turning on the function start button (not shown) of the present invention provided on the operation unit (steps 21, 22, and 23), the timer 7 starts operating and adjusts the electric field strength at predetermined intervals, for example, every 10 minutes. A clock is sent to the measurement control circuit 6 (steps 24 and 25).

The electric field strength measurement control circuit 6 measures the input electric field strength of a plurality of preset stations stored in the preset memory in the storage unit 3 for the control unit 2 every time it receives a clock from the timer 7. (Step 26). The control unit 2 receives a command from the field strength measurement control circuit 6, measures the input field strength of each preset station, and measures the input field strength of each station so that the input field strength is equal to or lower than the reference input field strength set in the field strength level setting circuit 5. Check whether there is a station (step 27).

If a station whose input field strength is below the standard is found, the station is memorized (step 28), and then the reception band is searched from the lower end of the band (step 29) to find stations other than those preset in the preset memory. Check whether the station is received (step 30).

If no other preset stations than those stored in the preset memory are being received, the contents of the preset memory are not changed and the state returns to the previous preset contents (step 31).

If a station other than the preset station stored in the preset memory is received, check whether the input field strength of the receiving station is equal to or higher than the reference input field strength set in the field strength level setting circuit 5. is determined (step 32), and if it is greater than the reference input electric field strength, this station is stored (step 33).
Similarly, it is checked whether there is a receiving station other than the preset station whose input field strength is equal to or higher than the standard input field strength across the entire receiving band (steps 34, 35, and 36), and each time a new receiving station is detected, The magnitude of the input electric field intensity is compared with the receiving station detected in the previous step, and the receiving station with the higher input electric field intensity is re-memorized (step 37).

Then, when the entire reception band has been searched (step 34), the last remaining receiving station with the highest input field strength is replaced with the preset station whose input field strength is less than the reference input field strength extracted in steps 27 and 28. It is stored in the set memory and preset as a new receiving station (step 38).

By automatically repeating the above operation every 10 minutes, only the best receiving stations in the area are automatically preset in the preset memory in the storage section 3. In step 27, if there are a plurality of preset stations whose input field strength is less than the reference input field strength, the newly detected receiving stations may be stored in order of increasing input field strength.

The above embodiment describes the case where the input electric field strength of the preset station is measured every 10 minutes, but if the time can be set freely at the discretion of the user or controller, its effectiveness will be further improved. To increase. Furthermore, although the above embodiments have been mainly described using an in-vehicle radio receiver as an example, the input electric field strength of a home radio receiver may also change due to changes in the timetable or frequency of the broadcasting station. Yes, it is fully applicable. especially,
This would be useful for portable receivers.

〔effect〕

According to the present invention, when the input electric field strength of the preset station stored in the preset memory becomes weak, stations other than the preset station with high input electric field strength are automatically preset. Only the best receiving stations in the area can be preset at all times, and even if the reception conditions change due to vehicle movement, etc., a station with only noise will not be called, and the best reception can always be performed. Furthermore, it is no longer necessary to perform the preset memory operation again at the destination, unlike in the conventional case, and the troublesome operation can be reduced. Furthermore, since the preset stations are automatically replaced, the tuning operation according to the present invention can be performed while listening to other audio equipment other than the radio, eliminating the need for preset waiting time as in the past. , you can use your time meaningfully, etc.
It has various excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a flowchart of its operation. 1... Receiving section, 2... Control section, 3... Storage section,
5... Electric field strength level setting circuit, 6... Electric field strength measurement control circuit, 7... Timer.

[Claims]

1. A latch circuit that detects and holds an input signal, a reference voltage generation circuit that sets a reference voltage according to the area ratio of the capacitor, and sets an input threshold level to the latch circuit using this reference voltage, and the latch. An input detection circuit that includes a buffer circuit that outputs an input signal from the circuit, and a dummy buffer circuit that compensates for the input/output balance of a latch circuit corresponding to the buffer circuit.