JPH0218773B2 - - Google Patents

Abstract

PURPOSE:To save the consumption of a power battery by using a fixed frequency oscillator of low power consumption in place of a PLL local oscillating circuit at standby state in a receiver having a standby reception function such as emergency call. CONSTITUTION:The fixed local oscillator 3 is provided for the reception of a specific frequency in a receiver where an oscillating voltage of a PLL control section 2 is applied to a mixer 12 to convert the reception frequency into an intermediate frequency. A switch 4 changes over the normal reception and the standby reception of the specific frequency and an oscillated output of the PLL control section 2 is selected at the normal reception. On the other hand, an output of the fixed local oscillator 3 is selected at the standby state for receiving the specific frequency and fed to the mixer 12. Since the power consumption of the PLL control section 2 is larger than that of the fixed local oscillator 3 in general, the power consumption of power battery is reduced considerably by switching the power to the position of the fixed local oscillator 3 at the standby state.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a general-purpose receiver for portable use, in-vehicle use, or in remote areas where commercial power is not available, and that is used for communication purposes, emergency calls, etc. when not in normal use. The present invention relates to a method for reducing battery consumption when applied to a receiver that is used for standby and reception, and which must remain in a reception standby state at all times.

[Conventional technology]

BACKGROUND ART Conventionally, receivers used on the move or in remote areas where commercial power is not available often use dry batteries as a power source.

[Problem to be solved by the invention]

However, in the conventional technology described above, the usage time of the receiver is affected by the lifespan of the dry cell battery, and especially for portable devices, it is desirable to use as small a battery as possible in terms of weight and volume, so the current consumption is minimized. It needs to be designed small. In addition, it is necessary to secure the minimum amount of current necessary to maintain the performance of the receiver, so when waiting for contact or emergency calls, for example, squelch control voltage is used to amplify the audio after the receiving detection stage. Conventional methods have been used to stop circuit operation and reduce current consumption. Since the audio output stage, which consumes the most current, normally operates in class B, the current consumption is small when there is no signal, and the savings achieved by stopping it cannot necessarily be said to be sufficient.

The present invention was made with the aim of improving these drawbacks of conventionally known radio receivers.

[Means to solve the problem]

This invention is a phase-locked loop (hereinafter referred to as
In a wireless receiver that sets the reception frequency using a controlled local oscillation frequency (abbreviated as PLL), the PLL circuit stops operating when it is in the standby state for radio waves of a specific frequency, and instead uses a frequency oscillator exclusively for standby and reception. This configuration solves the problems of the prior art described above.

〔Example〕

Next, the current consumption reduction method of the present invention will be explained based on the drawings. In the drawings, 1 is a receiving circuit, which is made up of an RF amplifier 1a, a mixer 1b, and an IF amplifier 1c. In addition, the PLL local oscillator 2 selectively tunes the reception frequency and is used during normal reception, and the crystal local oscillator 3
The crystal oscillator 3a is used for the purpose of obtaining the frequency necessary for receiving the frequency during standby. Further, if necessary, the oscillation frequency of the oscillator 3 can be changed by replacing the crystal oscillator 3a, so that the oscillator 3 can be tuned to a different standby/receive frequency. Further, if the oscillation circuit is a so-called non-adjustable circuit in this case, it is convenient because the standby/receive frequency can be changed when the crystal resonator 3a is replaced or switched by a switch or the like.

Note that the output of the PLL local oscillator 2 and the output of the crystal local oscillator 3 are connected in parallel to the mixer 1b of the receiving circuit 1.
However, since the power supply voltage of the PLL local oscillator 2 and crystal local oscillator 3 is switched by the power selector switch 4 so that only one of them oscillates, there is no problem in operation. be.

〔Effect of the invention〕

This invention reduces power consumption during normal reception by stopping the PLL control oscillation circuit, which consumes a relatively large amount of current, during standby reception in which the reception state continues for a long time. It has the effect of reducing the amount by half or less.

[Brief explanation of drawings]

The drawing is a block diagram for explaining the present invention. 1 ... Receiving circuit, 1a... RF amplifier, 1b...
...mixer, 1c...IF amplifier, 2...PLL local oscillator, 3 ...crystal local oscillator, 3a...crystal resonator, 4...power selector switch.

Claims (1)

[Claims] 1. In a wireless receiver of the type in which the reception frequency is set by a phase-locked loop controlled local oscillator, when waiting for radio waves of a specific frequency, the operation of the phase-locked loop controlled local oscillator is stopped, and the operation of the phase-locked loop controlled local oscillator is The current consumption reduction method during standby reception is characterized in that the power supply is switched to the phase-locked loop local oscillator during normal reception, and the power supply is switched to the specific frequency oscillator during standby reception.