Icom IC-R9000L [55/72] Tech talk from loom

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SCANN 9 6 SELECTED MODE MEMORY SCAN Selected mode memory scan repeatedly scans channels with the same selected operating mode S occurs in a bank or in all memory channels that selected by the memory scan bank SELECTED MODE MEMORY SCAN OPERATION 1 Set the memory scan bank See p 51 Section SETTING THE MEMORY SCAN RANGE steps Memory scan edges do not function in selecte memory scan 2 Select the desired resume condition See p 46 9 1 3 SCAN RESUME CONDITION 3 Adjust the SQUELCH control to the threshold poi 4 Select the desired mode to be scanned FM A etc FM MID 845 BANK SSQCH SEL MODE FM 112 001 SCAN CONDITION with MAIN DIAL While operating selected mode memory scan 5 Push MODE in the SCAN switches to start mode memory scan At least 2 memory channels with the same mo be programmed to operate scanning 6 Adjust the SPEED control to the desired speed 7 To stop scanning push a SCAN switch PROG etc or a CRT function switch F 1 The main dial also stops scanning Tech Talk from loom Q Why is it so difficult to increase scan speed A The most important factor determining scanning speeds is the PLL lockup time The faster the lockup time the faster the scanning speed However when lockup times increase the quality of VCO output signals C N decreases Decreased signal quality means the scan may not stop when a signal is received Lockup times and VCO signal quality therefore work against each other How to solve the problem Icom found a way By using the DDS Direct Digital Synthesizer in the PLL circuit the PLL creates a very short lockup time Using the DDS Icom succeeded in providing scanning speeds without decreasing the qua VCO output signals The scanning speed i IC R9000L is 13 channels second or more a s at least twice as fast as former Icom equip not equipped with the DDS system And yo be certain that the IC R9000L s scan will stop w signal is received

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