JPH02312370A - Television receiver - Google Patents

Abstract

PURPOSE:To drive an internal speaker and an external speaker with a signal of optimum voltage and frequency characteristic, respectively by switching the gain and the frequency characteristic of the internal speaker and the external speaker. CONSTITUTION:The gain and the frequency characteristic of a voice signal whose sound volume and sound quality are controlled with an audio control amplifier 1 is controlled to the one most suitable for respective speaker with a gain (f) characteristic switching circuit 2 interlocking with the change over switch 4 of the internal speaker and the external speaker, and is amplified with an audio power amplifier 3, then, the internal speaker 5 or the external speaker 6 selected by the change-over switch 4 is driven. Therefore, a sufficient power can be obtained when the external speaker 6 is driven, and the speaker is switched so as not to exceed the maximum rating when the internal speaker is driven. Thereby, each of the internal speaker 5 and the external speaker 6 can be driven with an electrical signal with the voltage and frequency characteristic most suitable for respective speaker.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a television receiver, and in particular to a television receiver that is capable of driving internal speakers and external speakers with electrical signals having optimal voltage and frequency characteristics. Regarding.

[Conventional technology]

Figure 3 is a block diagram of the external speaker switching circuit of a conventional television receiver. In the figure, 1 is an audio control amplifier that changes volume etc., 3 is an audio power amplifier that amplifies power, and 4 is an internal speaker. 5 is an internal speaker built into the television receiver, and 6 is an external speaker connected to an external connection terminal.

Next, the operation will be explained. The audio signal whose volume and sound quality are controlled by the audio control amplifier 1 is amplified by the audio power amplifier 3 to power capable of driving a speaker, and drives the speaker 5 or 6 selected by the changeover switch 4.

[Problem to be solved by the invention]

The external speaker switching circuit of a conventional television receiver is configured as described above, and the same voltage is applied to both the internal and external speakers. When designing a power amplifier, only the audio output of the same power can be output to the external speaker terminal, and in order to extract sufficient power from the external speaker, the internal speaker must also be used with an equivalent speaker, otherwise the rated power may be exceeded. There were also problems such as vibration occurring in the cabinet. Furthermore, if the frequency characteristics are designed to be flat in consideration of the connection of an external speaker, there are problems such as a poor sense of volume in the low range when the internal speaker is a small speaker.

This invention was made in order to solve the problems of the conventional ones as described above, and while using a speaker with a low rated power as an internal speaker, it can be driven with sufficient power when an external speaker is connected, and the internal speaker can be driven with sufficient power. The present invention aims to provide a television receiver in which the frequency characteristics of external speakers can be designed optimally.

[Failure to solve the problem]

The television receiver according to the present invention has a gain 8 frequency characteristic switching circuit that works with a speaker selection switch, and a switching circuit that controls the output voltage of the audio power amplifier to 9.
Internal speaker frequency characteristics.

Both external speakers can be switched to be optimal.

[Effect]

In this invention, with the above-described configuration, sufficient power can be obtained when driving an external speaker, and when driving an internal speaker, switching can be performed so as not to exceed the maximum rating of the speaker.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a television receiver according to an embodiment of the present invention. In the figure, 1 is an audio control amplifier, and 2 is a gain of 1 so that the output waveform of the amplifier 1 is optimized for each of the internal and external speakers. 3 is an audio power amplifier for amplifying the output of circuit 2 to power capable of driving a speaker; 3 is a gain 1 frequency characteristic switching circuit (hereinafter referred to as a gain f special switching circuit) for switching frequency characteristics;
is a changeover switch for switching between the internal speaker 5 and the external speaker 6.

Next, the operation will be explained.

Volume by audio control amplifier l.

The audio signal whose sound quality has been controlled is controlled to have the optimal gain and frequency characteristics for each speaker by a gain f special switching circuit 2 that works with the internal speaker and external speaker selection switch 4, and is then sent to an audio power amplifier 3.
, and drives the speaker 5 or 6 selected by the selector switch 4.

FIG. 2 shows an example of the configuration of the gain f special switching circuit 2, in which the resistor 8 is
, 9, 11, and a capacitor 10, when selecting an internal speaker, it is possible to reduce the signal amplitude, lower the high frequency range, and increase the volume of the bass.

Therefore, even when the internal speakers are downsized in order to downsize the television receiver body and reduce costs, sufficient power can be supplied to the external speakers.

Additionally, the internal speakers can be boosted to a moderate level without exceeding their maximum ratings.

In the above embodiment, a circuit that controls the signal line through a filter is shown as an example of a gain f specific switching circuit, but it may also be controlled by a negative feedback circuit of the audio power amplifier 3, or by the audio control amplifier 1. The same effect as in the above embodiment can be obtained.

In addition, although the above embodiment shows an example in which the low frequency range is boosted, it is also possible to use a special gain f switching method that compensates for the characteristics of the internal speaker (for example, by boosting the high frequency range). I don't mind.

Further, although the embodiment described above is applied to a television receiver, it can of course be applied to a radio cassette player, a handphone cassette, etc., and the same effects as in the embodiment described above can be obtained.

〔Effect of the invention〕

As described above, according to the television receiver of the present invention, since the gain 2-frequency characteristics are switched between the internal speaker and the external speaker, the respective speaker power is driven by a signal with the optimal voltage 2-frequency characteristics. The effect is that it can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a television receiver according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of the configuration of the gain r special switching circuit of FIG. 1, and FIG. 3 is a diagram showing a conventional example. be. In the figure, 1 is an audio control amplifier, 2 is a gain f special switching circuit, 3 is an audio power amplifier, 4 is a changeover switch, 5 is an internal speaker, and 6 is an external speaker. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a television receiver equipped with an external speaker terminal, there is a changeover switch that supplies the television audio signal to either the internal speaker or the external speaker, and a switch that controls the gain and frequency of the television audio signal in conjunction with the switch. A television receiver characterized by being equipped with a gain and frequency characteristic switching circuit that switches characteristics.