JPS609207A - Amplifier with tuner - Google Patents

Abstract

PURPOSE:To avoid application of muting to an input switch circuit part when an input selector selects a position excepting that of a tuner, by setting forcibly an input terminal for broadcast station detecting signal of an IC. CONSTITUTION:A diode 27 is connected forward to an input terminal 26 for broadcast station detecting signal from an input selector switching control terminal 13. When the selection position of the input selector is set at a tuner, the diode 27 does not conduct since the voltage of the terminal 13 is set at a low level. Then an IC1 has the same actuation as that obtained when no diode 27 exists. The voltage of the terminal 13 is set at a high level when the selection position of the input selector is set at a place other than the tuner. Thus the diode 27 conducts and the voltage of the terminal 26 is set at a high level although the voltage of an output terminal 25 for broadcast station detecting signal is set at a low level at a tuner part 2. Therefore the IC1 delivers no muting signal as long as the selection position of the input selector is set at a place other than the tuner and even if the voltage of the terminal 25 is changed to a low level from a high level. Thus, a phenomenon where no sound is delivered from a speaker is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an amplifier with a tuner whose input selector is electronically switched.

Configuration of conventional example and its problems Figure 1 is a block diagram of a conventional amplifier with tuner. 1 has a PLL frequency synthesizer for the tuner, and also has a controller function and a control signal output function for switching the input selector of the amplifier. The muting signal output when the input selector is switched or the muting signal output when the voltage of the broadcast station detection signal input terminal switches from high level to low level /l/ is output from the same terminal. Integrated circuit output from (hereinafter referred to as IC
2 is a tuner section, 3 is an input selector switching circuit section constituted by an electronic switch, 4 and 5 are low frequency signal input circuit sections, 6 is an amplifier circuit section, 7 is a speaker, and 8
9 is a muting signal input terminal of the tuner section 2; 1o is a muting signal input terminal of the input selector switching circuit section 3; 11,
12 and 13 are input selector switching control signal output terminals of IC1, 14, 16, and 16id input selector switching control signal input terminals of input selector switching circuit section 3, and 17, 18, and 19 are low frequency signal input circuit section 4, respectively. , 6 and a low frequency signal output terminal of the tuner section 2, 20
, 21 and 22 are low frequency signal input terminals of the input selector switching circuit section 3, 23 is a low frequency signal output terminal of the input selector switching circuit section 3, 24 is a low frequency signal input terminal of the amplifier circuit section 6, and 25 is a tuner section. 2 broadcast station detection signal output terminal, 26
is the broadcasting station detection signal input terminal of the unit C1.

The operation of the conventional amplifier with tuner configured as described above will be described below.

Tuner unit 2 outputs high level voltage and voltage to terminal 2 when receiving a broadcast signal, and low level voltage when not receiving a broadcast signal.
Output from 6. This voltage is input to the terminal 26 of the terminal C1. IO1 outputs a meeting signal from terminal 8 when the input selector is switched and when the pressure at terminal 26 is switched from high level to low level. This muting signal is applied to terminals 9 and 10, and muting is applied to tuner section 2 and input selector switching circuit section 3.

When one of the input selectors is selected using a switch not shown in the figure, only the terminal corresponding to the selected input selector among the terminals 11, 12, 13 of the ICI outputs a low level voltage, and the other terminals output a high level voltage. Outputs the full level voltage. Then, among the low frequency signal input terminals 20, 21, 22 corresponding to the control signal input terminals 14, 15, and 16 to which this voltage is input, the low frequency signal corresponding to the terminal whose controller signal input terminal is at low level. The low frequency signal at the signal input terminal is selected by the input selector switching circuit section 3 and output from the terminal 23.

This low frequency signal is inputted to the amplifier circuit section 6 from the terminal 24 and is heard as a sound from the speaker 7. When switching the input selector, a switching shock sound is generated, which is very annoying when heard from the speaker, so in order to eliminate this shock sound, the muting signal that is output from terminal 8 by the engineering C1 when switching the input selector is set to all input selector switching IB, υ is input to the circuit section through terminal 10, so that no sound is output from the speaker when the input selector is switched. Further, when listening to a broadcast received by the tuner section 2, only noise can be heard from the speaker when the broadcast ends, which is also extremely annoying. When the broadcast ends and the voltage at the broadcast station detection signal input terminal 26 of IC1 switches from high level to low level, 101 outputs a muting signal from terminal 8, and this muting signal is sent from terminal 9 to the tuner section. In addition, this is to prevent noise from appearing after the broadcast ends.

However, since IC1 outputs both the muting signal output when the input selector is switched and the muting signal output when the voltage of the broadcast station detection signal input terminal 26 switches from high level to low level from terminal 8, the above In the conventional configuration, even if the input selector is in a position other than the tuner, the input selector is switched when the voltage at the broadcast station detection signal input terminal 26 changes from high level to low level due to the end of a broadcast or a failure of the transmitter of the broadcast station. There was a problem that the circuit section 3 was muted and no sound came out from the speaker. ◇Object of the Invention The present invention solves the above conventional problems. When the input selector is in a position other than the tuner, the IC To provide an amplifier with a tuner that does not stop producing sound from a speaker even if the voltage of a broadcast station detection signal input terminal of the device is switched from high level to low level.

Composition of the Invention The present invention has a control signal output function for switching the input selector of an amplifier, and the voltage at the muting signal or broadcasting station detection signal input terminal output when switching the input selector changes from a high level to a low level. The muting signal that is output when switching is output from the same terminal.When the input selector selects a position other than the tuner, the voltage at the XC's broadcast station detection signal input terminal is always at a high level. By forcibly applying a high level voltage, muting will not occur even if the voltage of the broadcast station detection signal output from the tuner section changes from high level to low level. It is something that can be done.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a block diagram of an amplifier with tuner according to an embodiment of the present invention. 27 in Figure 2.
28 is a diode. Hereinafter, the operation of the tuner-equipped amplifier device of this embodiment having the configurations 9 and above, in which numerals 1 to 26 are the same as those of the conventional example, will be described below. The voltage at the input selector switching control terminal 13 is at a low level when the selected position of the input selector is the tuner, and is at a high level when the input selector is at any other selected position.

A diode is connected in the direction shown in Figure 2 from the terminal 13 to the broadcast station detection signal input terminal 26, and when the input selector selects the tuner, the voltage at the terminal 13 is at a low level, so the diode 27 is not conductive. First, IC1 operates in the same manner as in the conventional case without the diode 27. When the selected position of the input selector is other than the tuner, the voltage at the terminal 13 is at a high level, so the diode 27 becomes conductive, and the voltage at the broadcast station detection signal input terminal 26 is changed to the voltage at the broadcast station detection signal output terminal of the tuner section 2. Even if the voltage is low level, it becomes high level. Therefore, even if the voltage at the broadcast station detection signal output terminal 26 of the tuner section 2 changes from a high level to a low level due to the end of a broadcast or a failure of the transmitting device of the broadcast station, if the selected position of the input selector is other than the tuner, the C1
does not output a muting signal, and the phenomenon of no sound coming out of the speakers no longer occurs. The diode 28 functions to prevent the signal from the terminal 13 from flowing back into the tuner section 2 .

As described above, according to the present embodiment, the tuner section 2 Broadcasting station detection signal output terminal 2
Even if the voltage of 6 is switched from high level to low level, muting can be prevented from being applied to the input selector switching circuit section 3 when the manual selector is at a selection position other than the tuner.

Effects of the Invention The present invention has a control signal output function for switching the input selector of an amplifier, and the voltage at the muting signal output when the manual selector is switched or the voltage at the broadcast station detection signal output terminal changes from a high level to a low level. An IC capable of outputting a muting signal outputted from the same terminal when switching is made, and means for forcibly setting the voltage of the broadcast station detection signal input terminal to a high level when the input selector is at a selected position other than the tuner. By providing this, it is possible to realize an amplifier with a tuner that does not mute even if the voltage of the broadcast station detection signal output terminal of the tuner section switches from high level to low level when the input selector is in a selected position other than the tuner. .

[Brief explanation of the drawings] Figure 1 is a block diagram of a conventional amplifier with tuner, Figure 2 is a block diagram of a conventional amplifier with tuner.
The figure is a block diagram of an amplifier with tuner according to an embodiment of the present invention. 1...IC, 2...tuner section, 3.
...Input selector switching circuit section, 4, 5...
・Low frequency signal input circuit section, 6...Amplification circuit section,
7...Speaker, 27°28...Diode.

Claims (1)

[Claims] It has a control signal output function for switching the input selector of the amplifier, and is output when the muting signal output when the input selector is switched or the voltage of the broadcast station detection signal input terminal switches from high level to low level. a muting signal output from the same terminal; and means for forcibly setting the voltage of the broadcasting station detection terminal to a high level when the input selector selects a position other than the tuner. Amplifier with tuner.