device for improving the hoerkomforts through torment, the einschwingvorgaenge in a empfangskette a fm / pm schmalbandeinrichtung, especially for funkfernsprechen.

摘要

The present invention relates to a device for enhancing hearing comfort in a reception chain in narrow-band FM/PM equipment, in particular in radio-telephony comprising: - an HF head (11) situated at the antenna output (10); - at least one mixer (12, 16) receiving an oscillator signal (OS1, OS2); - a limiter/amplifier circuit (17); - a discriminator (18); - an LF amplifying circuit (20); - first means (22) of detecting and eliminating transient phenomena, situated at the output of the discriminator (18). These first means of detecting and eliminating the transient phenomena comprise: - on the one hand, first circuits connected in series between the input (A) and the output (F) of the said device, namely: . a delay line (30) whose group delay within the 300-3000 Hz frequency band is constant and has a value of about 150 mu s; . an analog switch (31); . a memory (32); - on the other hand, second circuits connected in series between the output (B) of the low-pass filter and a second input of the analog switch, namely; . a circuit for detecting transients (33); . a full-wave rectifier (34); . a logic unit (35) for controlling the switch, allowing generation of a window with a width of about 500 mu s in which the delay line allows centring of the interference. Application in particular to the field of radio-telephony. IMAGE