JPH04102263A - Receiving signal recorder - Google Patents

Abstract

PURPOSE:To make a recording medium efficient and to accurately record information by operating a recorder to record a signal only when it is inputted in a discriminating circuit composed of a low band filter and a high band filter, etc. CONSTITUTION:An intermediate frequency input signal S1 is outputted as a demodulated signal S2 by a demodulation circuit 2. Noise or the demodulated signal S2 as the receiving signal are separated into two frequency components by the low band filter 8 and the high band filter 9 and compared with each other in level by a comparator circuit 10. An S/N discriminating signal S6 to be outputted by the circuit 10 is outputted as an S discriminating signal S8 from an arithmetic processing circuit 12. A squelch signal S9 is outputted by a logarithmic amplifier cuit 13, a detecting circuit 3 and a detecting level setting volume 6 and a comparator circuit 4. The S discriminating signal S8 and the squelch signal S9 are passed through an AND circuit 14 to become a recording control signal S5 for operating the recorder 5 to carry out its recording operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voice or data receiver, and more particularly to a received signal recording device for recording received voice and data.

[Conventional technology]

A conventional received signal recording device uses a circuit (squelch circuit) for detecting the presence or absence of a received input signal as shown in FIG. In the figure, a detection circuit 3 is provided after the intermediate frequency amplification circuit 1, and when the level of the intermediate frequency input signal S1 increases, a recording control signal S5 is output to the recorder 5, and the demodulation circuit 2
The data demodulated is recorded by the recorder 5.

Further, the detection level is set using the volume 6.

[Problem to be solved by the invention]

Conventional received signal recording devices output a recording control signal when the input signal level becomes high, so even when large noise is input, the recorder operates and records unnecessary noise. Furthermore, since there is a time period from when the control signal is output until the recorder starts operating, the first part of the input signal is cut off and recorded. Since the detection circuit is installed after the intermediate frequency amplifier circuit, which is a common circuit for detecting input signals, the detection output has a narrow linear range with respect to the input signal, making it impossible to set the detection level appropriately over a wide range. There was a problem.

Means for Solving the Problem] In the received signal recording device of the present invention, the output output from the demodulation circuit is divided into high and low frequency bands, their levels are compared, and if there is a level difference, It is determined that it is a signal and controls the recording of the recorder.

Absolute excuse] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, in which an intermediate frequency input signal S1 is outputted by a demodulation circuit 2 as a demodulated signal S2. The demodulated signal S2, which is noise or a received signal, is divided into two frequency components by a low-pass filter 8 and a high-pass filter 9, and the levels are compared by a comparison circuit 10. The number and time of comparisons are determined by the sample and hold signal S7.

In the arithmetic processing circuit 12, the S/N discrimination signal S6 outputted by the comparator circuit 10 is compared six times, and if the number of times is three or more, it is determined to be a signal, and an S judgment signal is generated. Output S8. Demodulated signal 82 input to the recorder
'' is delayed by the delay circuit 7 by the sum of the processing time of the above-mentioned discrimination circuit and the start-up time of the recording operation of the recorder.

The present invention further includes a detection level setting means (squelch circuit), which is a logarithmic amplifier circuit 12. Detection circuit 3. It is composed of a detection level setting volume 6 and a comparison circuit 4, and outputs a squelch signal S. The S determination signal S8 and the squelch signal S pass through an AND circuit 14 and become a recording control signal S5 that causes the recorder to perform a recording operation.

〔Effect of the invention〕

As explained above, the present invention records the demodulated signal of the receiver by operating the recorder only when the signal is input using the S/N discriminating circuit composed of a reduction filter, a high-pass filter, etc. This has the effect of increasing the efficiency of the medium, preventing the beginning of the recorded signal from being cut off by the delay circuit, and recording information accurately.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional embodiment. 1...Intermediate frequency amplification circuit, 2...Demodulation circuit, 3...Detection circuit, 4.10...Comparison circuit, 5...lz=+ -da, 5...detection level setting volume, 7...delay circuit, 8...
...Low pass filter, 9...High pass filter, 11...
...Sample and hold signal generation circuit, 12...
Arithmetic processing circuit, 13... Logarithmic amplifier circuit, 14.
...AND circuit, s,,s,'...Intermediate frequency input signal, S2+82', S2...Demodulated signal, S3...Detected output signal, S4... ...Detection level setting signal, S5... Recording control signal, S
6...Sample hold signal, S7...
・S/N discrimination signal, S8...S judgment signal, S9・
...Squelch signal. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] a recorder for recording the demodulated audio or data output; a reduction filter and a high-pass filter for receiving the demodulated signal; a comparing means for comparing the outputs of the two filters to determine whether the signal is noise or a signal; The present invention relates to a received signal recording apparatus characterized by comprising a control means for outputting the output of the comparison means to the recorder as a recording control signal.