It seems quite simple when one thinks of choosing a frequency to operate ones crystal oscillator for timing, PLLs etc. However, apart from the obvious issues associated with the actual operation of the circuit it becomes important to select a crystal frequency that is relatively easy to source. For instance we have a RF transmitter and a RF receiver. This time we chose these off the shelf instead of developing our own chip. The transmitter has a crystal frequency of 14.3 Mhz. This is an easy one to source. Digikey has a number of these crystals for immediate delivery. However, the receiver crystal frequency is specified as 14.464063 Mhz. This is a killer. We cannot source this crystal easily. There is a long wait for it and many dollars for development. So we are now in a predicament. After much deliberation we are going with a crystal oscillator dissipating 32 mA for our first demo system. The issue is that the battery will be discharged very quickly. The search for the correct crystal continues…