JPH01133429A - Radio receiver - Google Patents

Abstract

PURPOSE:To make the time required for making re-turning shorter, by selecting a specific preset receiving frequency and performing preset searching for reception when the intensity of the electric field of a receiving station becomes weaker. CONSTITUTION:When it is detected by a level deciding circuit 8 that the intensity of the electric field of the currently receiving station becomes weaker, frequency data M1 in a preset memory 7 are sent to a PLL circuit 6 by means of a preset circuit 9. When the intensity of the electric field of a new receiving frequency M1 is discriminated as sufficient for reception by the circuit 8 thereafter, the frequency M1 is received. When the frequency M1 is discriminated that its electric field has no sufficient intensity, a next frequency M2 is sent to the PLL circuit 6 from the memory 7 and, when a station having a sufficient field intensity is not selected, the above-mentioned operation is repeated. When intensities of electric fields to all of the frequencies in the memory 7 are inefficient, auto-search is started by an auto-search circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention is directed to a radio receiver having an auto-retune function that automatically changes the receiving frequency and performs re-tuning when the electric field strength of the receiving station becomes weak. Regarding machines.

(b) Conventional technology In a radio receiver having an auto-retune function,
Conventionally, when the electric field strength of the receiving station becomes weak, an automatic search is simply performed to automatically change the reception frequency and lock the PLL at the position where the electric field strength is strong.

(c) Problems to be solved by the invention Conventional radio receivers with an auto-retune function:
When the field strength of the receiving station falls below a preset standard, the auto-retune function initiates an auto-search operation. At this time, reception is performed while continuously changing the receiving frequency, and while determining the electric field strength at each time, a frequency band with a strong electric field strength is searched for, the PLL is locked, and a new station is received. Therefore, it took time to retune to a new station.

Therefore, an object of the present invention is to shorten the time required for retuning.

(d) Means for solving the problem The above problem consists of a PLL circuit and a preset system that stores in advance a plurality of reception frequencies received by the PLL circuit.
a memory, a level determination circuit that constantly determines the field strength of received radio waves, and outputs a control signal to start a preset search when the field strength decreases and falls below a preset standard; and the level determination circuit. a preset circuit that sequentially selects frequency data stored in the preset memory and supplies it to the PLL circuit in accordance with a control signal output by the circuit; and an electric field strength that satisfies a standard in the frequency data in the preset memory. The problem is solved by a radio receiver having a reception discrimination circuit that outputs a control signal to start an auto search when there is no broadcast station, and an auto search circuit that starts an auto search in response to the output control signal of the reception discrimination circuit. Ru.

(*°) Effect According to the present invention, when the received electric field strength falls below a set standard, frequency data stored in a preset memory is called up and that station is received. If the electric field strength of a newly received station is sufficient, that station is received; if it is insufficient, the frequency data is changed to another one. If there is no broadcasting station with a field strength that satisfies the standard in the frequency data in the preset memory, the system automatically shifts to auto search operation.

(f) Example The configuration of an example of the present invention is shown in FIG. 1. In the figure, (l) is a high frequency amplifier circuit, (2) is a mixing circuit, and (3) is a high frequency amplifier circuit.
is an intermediate frequency amplifier circuit, (4) is a detection circuit, (5) is a demodulation circuit, (6) is a PLL circuit including a voltage controlled oscillator and a programmable divider, and (7) is a PLL circuit (6).
) to pre-memorize the frequency data to be supplied to
The memory (8) is a level determination circuit that outputs a control signal "L" when the field strength of the received radio wave is above a preset standard, and outputs a control signal "H" when it is below.

(9) continues to receive the current receiving station when the control signal "L" from the level judgment circuit (8) is input, and stores it in the preset memory (7) when the control signal 'H' is input. The stored frequency data is sequentially selected and the PLL circuit (6
), (10) is the preset circuit that supplies the
If there is no broadcasting station with a field strength that satisfies the standard in the frequency data in the memory (7), a reception discrimination circuit outputs a control signal "H" to start auto search, and (11) is a reception discrimination circuit (10). It starts when the output control signal “H” is input, automatically changes the receiving frequency, and the level judgment circuit (
This is an auto search circuit that locks the PLL and receives the frequency when the control signal "L" from 8) is input.

FIG. 2 is a flowchart showing the operation of the above embodiment. In addition, in the same figure, there are presets that can be stored in advance.
The number of memories is six, and each frequency is ~H6.

Hereinafter, the operation of the above embodiment will be explained according to this flowchart. When the level judgment circuit (8) detects a lack of electric field strength of the station currently being received, it outputs a control signal 'H', and when this control signal is input to the preset circuit (9), a preset search is started. First, frequency data 1 in the preset memory (7) is sent to the PLL circuit (6).The level determination circuit (8) determines whether the electric field strength of the new reception frequency H3 is sufficient.Preset circuit (9) If the control signal "L" is input from the level determination circuit (8), the preset search operation is stopped and Ml is received as is.Furthermore, when the control signal "H" is input, the next frequency H3 is sent to the PLL circuit (6). If a station with sufficient field strength cannot be obtained, these operations are repeated until H1 is reached. As a result, the preset memory (
7), when the electric field strength of all the frequency data (M, to M,) is insufficient, the reception discrimination circuit (10) outputs a control signal "H" to start an auto search.

When this control signal "H" is input to the auto search circuit (11), auto search can be started. The reception frequency of the PLL circuit (6) is changed by the auto search circuit (11). The electric field strength of the frequency at this time is also judged at any time by the level judgment circuit (8), and when the control signal 'L'' of the level judgment circuit (8) is fully input to the auto search circuit (11), the PLL is locked and the automatic The search operation is stopped and a new station is received.

As described above, according to the radio receiver of the present invention, when changing the reception frequency using the auto-retune function, a preset search is first performed to select and receive a frequency that has been stored in the preset memory in advance, which is different from the conventional method. The time required to receive a new station is shortened compared to a method using only automatic search, in which the receiving frequency is changed on a trial basis to find a place with a strong electric field strength and receive the signal.

(G) Effects of the Invention According to the radio receiver of the present invention, when the electric field strength of the receiving station becomes weak, the preset search operation is started in which a specific preset receiving frequency is selected and received.
The time required to re-tune to a new station is shortened compared to conventional auto-search in which the reception frequency is changed continuously and on a trial basis, and if there is a location where the electric field strength is strong, the reception frequency is received.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a radio receiver of the present invention;
FIG. 2 is a flowchart showing the operation of the embodiment of the radio receiver of the present invention. (Explanation of symbols) (6)...PLL circuit, (7)...Preset memory, (8)...Level judgment circuit, (9)...Preset circuit, (10)...Reception Discrimination circuit, (11
)...Auto search circuit.

Claims (1)

[Claims] (1) A PLL circuit, a preset memory that stores in advance a plurality of reception frequencies received by the PLL circuit, and a preset memory that constantly determines the field strength of received radio waves, and as a result, the field strength decreases to a preset value. a level determination circuit that outputs a control signal to start a preset search when the level is below a reference; and a PLL circuit that sequentially selects frequency data stored in the preset memory in accordance with the control signal output from the level determination circuit. a reception determination circuit that outputs a control signal to start auto search if there is no broadcasting station with a field strength that satisfies the standard in the frequency data in the preset memory; A radio receiver having an auto search circuit that starts auto search in response to an output control signal.