Icom IC-7850 Instruction Manual - Page 79

Previous view 5 RECEIVE AND TRANSMIT This section, describes particular operations for each operating mode, such as operating the Memory keyer in the CW mode, or operating the Encoder or Decoder in the RTTY or PSK mode. If you use functions that are described in Section 6: Scope operation, Section 7: Functions for Receive, or Section 8: Functions for Transmit, you can operate the transceiver more conveniently. ■■Convenient functions for Receive  All operating modes Preamplifier (p. 7-2) The preamp amplifies received signals in the receiver front end, to improve the S/N ratio and sensitivity. When receiving weak signals, select to P.AMP 1 or P.AMP 2. ➥➥Push [P.AMP] several times to turn ON preamp 1 or preamp 2 or, to turn OFF the preamp. • "P.AMP1" or "P.AMP2" is displayed when preamp 1 or preamp 2 is ON. (The Main and Sub bands have independent preamp controls.) Attenuator (p. 7-2) The attenuator prevents a desired signal from becoming distorted when very strong signals are near the frequency, or when very strong electric fields, such as from broadcasting stations, are near your location. ➥➥Push [ATT] several times to set the attenuator in 6 dB steps. • Hold down [ATT] for 1 second to set the attenuator in 3 dB steps. • "ATT" and the attenuation level are displayed when the attenuator is ON. Notch filter (p. 7-13) The Auto notch function uses DSP to automatically attenuates beat tones, tuning signals, and so on, even if they are moving. The Manual notch can be set to attenuate a frequency by rotating the [NOTCH] control. • When the SSB or AM mode is selected: Auto notch or Manual notch can be used. • When the CW, RTTY, or PSK mode is selected: Only the Manual notch can be used. • When the FM mode is selected: Only the Auto notch can be used. ➥➥Push the [NOTCH] key to turn the Auto or Manual notch function ON or OFF. • Rotate the [NOTCH] control to set the "valley" frequency for the Manual notch function. • The Notch indicator (above the [NOTCH] key) lights when either the Auto or Manual notch function is ON.  SSB/CW/RTTY/PSK/AM modes Noise blanker (p. 7-11) The noise blanker eliminates pulse-type noise such as the noise from car ignitions. ➥➥Push the [NB] key to turn the noise blanker ON or OFF, and then rotate the [NB] control to adjust the threshold level. • The Noise blanker indicator (above the [NB] key) lights when the noise blanker is ON. • Hold down the [NB] key for 1 second to enter the Noise blanker set screen. Noise reduction (p. 7-12) The Noise reduction function reduces random noise components and enhances desired signals that are buried in noise. The DSP does the random noise reduction function. ➥➥Push the [NR] key to turn the Noise reduction ON or OFF. • Rotate the [NR] control to adjust the noise reduction level. • The Noise reduction indicator (above the [NR] key) lights when the Noise reduction is ON. AGC (p. 7-4) The AGC (Auto Gain Control) controls receiver gain to produce a constant audio output level even when the received signal strength greatly varies. Twin PBT (p. 7-5) The PBT (Passband Tuning) electronically narrows the IF passband width by shifting the IF frequency to slightly outside of the IF filter passband, to reject interference. The IC-7850 uses DSP for the PBT function. Moving both the [TWIN PBT] controls to the same position shifts the IF. ➥➥Rotate the [TWIN PBT] controls (inner/outer). • Hold down [PBT CLEAR] for 1 second to clear the settings. 5-2